Load throwing protection circuit of starting battery and power supply device of new energy automobile

Abstract

The utility model provides a throw load protection circuit of a starting battery and a power supply device of a new energy automobile. The throw load protection circuit is connected in series between a battery bus cathode and a battery bus anode of the starting battery. The throw load protection circuit comprises a one-way switch unit and an energy storage unit which are connected in series; the cathode of the energy storage unit is connected to the cathode of a battery bus of the starting battery, and the anode of the one-way switch unit is connected to the anode of the battery bus of the starting battery, so that when the starting battery is normally charged, the load throwing protection circuit does not work; when the charging switch is switched off, the load throwing protection circuit is switched to be connected with the generator in series to form a follow current loop. Compared with a scheme of adding a string of super capacitors between the positive electrode and the negative electrode of the starting battery, the cost is reduced; when the load throwing protection is carried out, the starting battery does not participate in the follow current process when the load throwing protection is carried out, the starting battery is isolated, and the safety is higher.

Description

Technical Field

[0001] This utility model relates to the field of power supply device technology, specifically to a load dump protection circuit for a starting battery and a power supply device for new energy vehicles. Background Technology

[0002] Lithium-ion batteries have advantages such as high energy density, small size, and long lifespan. Currently, automakers widely use lithium-ion batteries (especially lithium iron phosphate batteries) instead of lead-acid batteries for vehicle starting. After the vehicle starts, the onboard alternator supplies power to the vehicle's equipment and simultaneously charges the starting battery. During charging, a protection board is required to prevent overcharging. When the starting battery is fully charged, the protection board will activate overcharge protection and shut off the charging switch to prevent overcharging from causing overvoltage in individual cells. After the overcharge protection board activates, an induced high voltage will be generated between the output buses P+ and P- due to the disconnected charging switch. This can not only cause the alternator to experience load shedding, but the excessively high alternator output voltage can also affect the normal operation of the onboard equipment and even damage it.

[0003] Currently, to prevent generator load dumping, the mainstream solution for making a starter battery protection board is to add a series of supercapacitors between the positive and negative terminals of the starter battery, which has a relatively high application cost.

[0004] Unlike the mainstream solution, a utility model patent document published on December 10, 2024, with authorization announcement number CN 222147192 U, discloses a load dump protection circuit for a starter battery and a power supply device for a new energy vehicle. This includes a freewheeling circuit formed in series between the load dump protection circuit and the starter battery at the moment the charging switch is turned off. An energy storage unit absorbs energy, thereby stabilizing the voltage between the positive and negative terminals of the battery bus below a preset threshold. In this patent document's solution, during load dump protection, both the starter battery and the energy storage unit capacitor of the load dump protection circuit participate in the freewheeling process; that is, the starter battery must participate in the freewheeling process during load dump protection.

[0005] In order to solve the above problems, people have been seeking an ideal technological solution. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a load dump protection circuit for a starting battery and a power supply device for new energy vehicles. This not only solves the problem of excessively high costs in current mainstream solutions, but also addresses the issue of the starting battery having to participate in the freewheeling process during load dump protection.

[0007] To achieve the above objectives, the first aspect of this utility model provides a load dump protection circuit for a starting battery, wherein a control circuit is connected in series between the negative terminal of the starting battery and the negative terminal of the battery bus, and the control circuit includes a charging switch.

[0008] The load dumping protection circuit is connected in series between the negative terminal and the positive terminal of the starting battery bus.

[0009] The load dump protection circuit includes a unidirectional switching unit and an energy storage unit connected in series.

[0010] The negative terminal of the energy storage unit is connected to the negative terminal of the starting battery bus, and the positive terminal of the one-way switching unit is connected to the positive terminal of the starting battery bus, so that:

[0011] When the starting battery is charging normally, the load dump protection circuit does not work;

[0012] When the starting battery is overvoltaged, the charging switch is turned off at the instant the starting battery is disconnected, and the load dump protection circuit is switched to form a freewheeling circuit in series with the generator. The energy storage unit absorbs the energy in the freewheeling circuit and stabilizes the voltage between the positive and negative terminals of the battery bus below a preset threshold.

[0013] Based on the above, the preset threshold is 28V.

[0014] Based on the above, the load dump protection circuit also includes a discharge resistor connected in parallel with the energy storage unit.

[0015] Based on the above, the load dump protection circuit also includes a reverse connection protection device, which is connected in series between the positive terminal of the unidirectional switch unit and the positive terminal of the battery bus of the starting battery.

[0016] Based on the above, the reverse connection protection device is a diode.

[0017] Based on the above, the unidirectional switching unit is a Zener diode.

[0018] Based on the above, the energy storage unit is a supercapacitor or is formed by multiple electrolytic capacitors connected in parallel.

[0019] Based on the above, the control circuit also includes a discharge switch.

[0020] Based on the above, the starting battery is a lithium-ion battery.

[0021] To achieve the above objectives, a second aspect of this utility model provides a power supply device for a new energy vehicle, including a starter battery, a discharge switch, a charging switch, a control module, and a load dump protection circuit; the control module is used to monitor the voltage of the starter battery and to control the opening and closing of the discharge switch and the charging switch; the load dump protection circuit is a load dump protection circuit for any of the above-mentioned starter batteries.

[0022] This utility model has substantial features and advancements compared to the prior art, specifically:

[0023] (1) When the charging switch is turned off, the charging circuit between the generator and the starting battery is disconnected in the load dumping protection circuit of this utility model. Only the load dumping protection circuit and the generator form a freewheeling circuit, and the energy is absorbed through the energy storage unit, thus avoiding the generator from dumping load.

[0024] (2) The energy storage unit in the load dump protection circuit of this utility model only requires one supercapacitor or multiple electrolytic capacitors. Compared with the traditional solution of adding a string of supercapacitors between the positive and negative terminals of the starting battery when making a starting battery protection board, the solution of this utility model reduces the cost.

[0025] (3) The load dump protection circuit of this utility model is connected in series between the negative terminal of the battery bus and the positive terminal of the battery bus of the starting battery. When the load dump protection is performed, the starting battery does not participate in the freewheeling process during the load dump protection. Only the freewheeling circuit is formed between the load dump protection circuit and the generator, which isolates the starting battery and makes it safer. Attached Figure Description

[0026] Figure 1 This is a schematic block diagram of the structure of a load dump protection circuit for a starting battery according to this utility model.

[0027] Figure 2 This is a schematic diagram of the circuit principle of a load dump protection circuit for a starting battery according to this utility model.

[0028] Figure 3 This utility model is a schematic diagram of the circuit principle of a power supply device for new energy vehicles, including a discharge switch and a control module. Detailed Implementation

[0029] The technical solution of this utility model will be further described in detail below through specific embodiments.

[0030] The terms "first," "second," "third," "fourth," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Example 1

[0031] As attached Figure 1 As shown in the figure, this embodiment provides an implementation method for a load dump protection circuit for a starting battery.

[0032] A load dump protection circuit for a starting battery, wherein a control circuit is connected in series between the negative terminal of the starting battery and the negative terminal of the battery bus, and the control circuit includes a charging switch;

[0033] The load dumping protection circuit is connected in series between the negative terminal and the positive terminal of the starting battery bus.

[0034] The load dump protection circuit includes a unidirectional switching unit and an energy storage unit connected in series.

[0035] The negative terminal of the energy storage unit is connected to the negative terminal of the starting battery bus, and the positive terminal of the one-way switching unit is connected to the positive terminal of the starting battery bus, so that:

[0036] When the starting battery is charging normally, the load dump protection circuit does not work;

[0037] When the starting battery is overvoltaged, the charging switch is turned off at the instant the starting battery is disconnected, and the load dump protection circuit is switched to form a freewheeling circuit in series with the generator. The energy storage unit absorbs the energy in the freewheeling circuit and stabilizes the voltage between the positive and negative terminals of the battery bus below a preset threshold.

[0038] It should be noted that this embodiment implements one method of load dump protection for the battery's load dump protection circuit:

[0039] In this implementation, the on-state voltage of the unidirectional switch unit is less than the overvoltage protection voltage.

[0040] When the charging switch is closed, the on-board generator is started to charge the starter battery. When the voltage of the starter battery is less than the conduction voltage of the one-way switch unit, the load dump protection circuit does not work, the charging switch is in the closed state, and a charging circuit is formed between the generator and the starter battery through the charging switch.

[0041] The starting battery continues to be charged. When the voltage of the starting battery is greater than the conduction voltage of the one-way switch unit but less than the overvoltage protection voltage, the one-way switch unit is turned on, and current flows through the load dump protection circuit. The load dump protection circuit absorbs energy through the energy storage unit. At the same time, the charging switch remains closed, and a charging circuit is still formed between the generator and the starting battery through the charging switch.

[0042] As the voltage of the starting battery continues to rise, when the voltage of the starting battery is greater than or equal to the overvoltage protection voltage, the charging switch is turned off, the conduction circuit between the generator and the starting battery is broken, and only the generator and the load dump protection circuit form a freewheeling circuit, thus avoiding the generator from dumping load (i.e., avoiding the generation of induced high voltage between the positive and negative terminals of the generator at the moment the charging switch is turned off).

[0043] This embodiment demonstrates another way to implement load dump protection in the battery's load dump protection circuit:

[0044] In this implementation, the on-state voltage of the unidirectional switch unit is greater than the overvoltage protection voltage.

[0045] Close the charging switch to start the vehicle generator to charge the starter battery; when the voltage of the starter battery is lower than the overvoltage protection voltage, the load dump protection circuit does not work, the charging switch is in the closed state, and a charging circuit is formed between the generator and the starter battery through the charging switch.

[0046] When the voltage of the starting battery reaches the overvoltage protection voltage, the charging switch is turned off, the conduction circuit between the generator and the starting battery is broken, and only the generator and the load dump protection circuit form a freewheeling circuit, thus avoiding the generator from dumping load (that is, avoiding the generation of induced high voltage between the positive and negative output terminals of the generator at the moment the charging switch is turned off).

[0047] In this embodiment, the load dump protection circuit is connected in series between the negative terminal and the positive terminal of the starting battery bus. When load dump protection is performed, the starting battery does not participate in the freewheeling process during load dump protection. Only the load dump protection circuit and the generator form a freewheeling loop, which isolates the starting battery and provides higher safety.

[0048] Furthermore, in this embodiment, the energy storage unit is a supercapacitor or formed by multiple electrolytic capacitors connected in parallel. Compared to the traditional approach of adding a string of supercapacitors between the positive and negative terminals of the start-up battery when making a start-up battery protection board, the energy storage unit in the load dump protection circuit of this embodiment only requires one supercapacitor or multiple electrolytic capacitors, which greatly reduces the cost of use. Example 2

[0049] The difference between this embodiment and Embodiment 1 is that the load dump protection circuit for the starting battery also includes a discharge resistor connected in parallel with the energy storage unit. The discharge resistor can be composed of multiple resistors connected in series and parallel.

[0050] The energy in the energy storage unit is quickly released by the discharge resistor. Example 3

[0051] The difference between this embodiment and Embodiment 2 is that the load dump protection circuit of the starting battery further includes a reverse connection protection device, which is connected in series between the positive terminal of the unidirectional switch unit and the positive terminal of the battery bus of the starting battery.

[0052] It should be noted that the function of the reverse connection protection device is to prevent the load dump protection circuit from working when the positive terminal of the reverse connection protection device is connected to the negative terminal of the battery bus.

[0053] The reverse connection protection device can be a diode. Example 4

[0054] This embodiment provides a specific implementation of a load dump protection circuit for a starting battery.

[0055] In this embodiment, the unidirectional switching unit is a Zener diode, for example.

[0056] like Figure 2 As shown, N-channel MOSFET Q2 is the charging switch, capacitor C1 is the energy storage unit, resistor R1 is the bleeder resistor, Zener diode D2 is the unidirectional switching unit, diode D1 is the reverse connection protection device, B- is the battery negative terminal, B+ is the battery positive terminal, P+ is the battery bus positive terminal, and P- is the battery bus negative terminal. The energy storage unit, bleeder resistor, unidirectional switching unit, and reverse connection protection device together form a load dump protection circuit.

[0057] like Figure 2 As shown, in one embodiment: the Zener diode D2 has a Zener voltage of 28 volts; the normal operating voltage of the startup battery is approximately 26 volts;

[0058] The load dump protection principle in this embodiment is as follows:

[0059] When the starter battery is first charged, its voltage is lower than the voltage regulation voltage (28 volts) of the Zener diode D2. As the charging time increases, the voltage of the starter battery will gradually increase.

[0060] During the charging process of the starting battery, when the voltage of the starting battery is less than the voltage regulation voltage (28 volts) of the Zener diode D2, the charging switch is in the closed state, the load dump protection circuit does not work, and the generator and the starting battery form a charging circuit.

[0061] As the starting battery continues to charge, its voltage will increase and gradually reach the voltage regulation voltage of the Zener diode D2. When the starting battery voltage is greater than the Zener diode D2 voltage but less than the overvoltage protection voltage, the charging switch remains closed, the Zener diode D2 conducts, and the generator and starting battery form a charging circuit, with capacitor C1 absorbing energy.

[0062] As the voltage of the starting battery increases, when the voltage of the starting battery is greater than or equal to the overvoltage protection voltage, the overvoltage protection disconnects the charging switch, the charging circuit between the starting battery and the generator is disconnected, and the load dump protection circuit continues to maintain the load of the generator. Only the load dump protection circuit and the generator form a freewheeling circuit. Capacitor C1 absorbs energy and resistor R1 discharges energy, thereby avoiding the load dump phenomenon and solving the problem in the prior art that the starting battery must participate in the freewheeling process when the load dump protection is applied.

[0063] In one embodiment, the preset threshold is 28V. Example 5

[0064] The difference between this embodiment and the above embodiments is that the control circuit further includes a discharge switch.

[0065] Once the starter battery is fully charged, it can be discharged via a discharge switch.

[0066] In one embodiment, the discharge switch is an N-channel MOSFET.

[0067] In one embodiment, the starting battery is a lithium-ion battery. Example 6

[0068] like Figure 3 As shown in the figure, this embodiment provides a power supply device for a new energy vehicle, including a starter battery, a discharge switch, a charging switch, a control module, and a load dump protection circuit; the control module is used to monitor the voltage of the starter battery and to control the opening and closing of the discharge switch and the charging switch; the load dump protection circuit is the load dump protection circuit described in any of the above embodiments.

[0069] It should be noted that when the starting battery voltage is lower than the overvoltage protection voltage, the control module controls the charging switch to close; when the starting battery voltage is greater than or equal to the overvoltage protection voltage, the control module controls the charging switch to open. When it is necessary to discharge the starting battery, the control module controls the charging switch to open and the discharging switch to close to allow discharge.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. A load dump protection circuit for a starting battery, wherein a control circuit is connected in series between the negative terminal of the starting battery and the negative terminal of the battery bus, the control circuit including a charging switch; Its features are: The load dumping protection circuit is connected in series between the negative terminal and the positive terminal of the starting battery bus. The load dump protection circuit includes a unidirectional switching unit and an energy storage unit connected in series. The negative terminal of the energy storage unit is connected to the negative terminal of the starting battery bus, and the positive terminal of the one-way switching unit is connected to the positive terminal of the starting battery bus, so that: When the starting battery is charging normally, the load dump protection circuit does not work; When the starting battery is overvoltaged, the charging switch is turned off at the instant the starting battery is disconnected, and the load dump protection circuit is switched to form a freewheeling circuit in series with the generator. The energy storage unit absorbs the energy in the freewheeling circuit and stabilizes the voltage between the positive and negative terminals of the battery bus below a preset threshold.

2. A throw load protection circuit for a starting battery as defined in claim 1, characterized in that: The preset threshold is 28V.

3. The throw load protection circuit for a starting battery of claim 1 wherein: The load dump protection circuit also includes a discharge resistor connected in parallel with the energy storage unit.

4. The throw-put load protection circuit for a starting battery of claim 1 wherein: The load dump protection circuit also includes a reverse connection protection device, which is connected in series between the positive terminal of the unidirectional switch unit and the positive terminal of the battery bus of the starting battery.

5. A throw load protection circuit for a starting battery as defined in claim 4, wherein: The reverse connection protection device is a diode.

6. A throw-charge protection circuit for a start battery as claimed in any one of claims 1 to 5, characterized in that: The unidirectional switching unit is a Zener diode.

7. A throw-charge protection circuit for a start battery as claimed in any one of claims 1 to 5, wherein: The energy storage unit is a supercapacitor or is formed by multiple electrolytic capacitors connected in parallel.

8. A throw-charge protection circuit for a start battery as claimed in any one of claims 1 to 5, wherein: The control circuit also includes a discharge switch.

9. A throw-charge protection circuit for a start battery as claimed in any one of claims 1 to 5, wherein: The starting battery is a lithium-ion battery.

10. A power supply device for a new energy vehicle, characterized in that: It includes a starter battery, a discharge switch, a charging switch, a control module, and a load dump protection circuit; the control module is used to monitor the voltage of the starter battery and to control the opening and closing of the discharge switch and the charging switch; the load dump protection circuit is the load dump protection circuit of the starter battery as described in any one of claims 1 to 9.

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