Battery hardware protection circuit, power battery

Abstract

This utility model discloses a battery hardware protection circuit and a power battery. The protection circuit includes multiple voltage detection units, multiple temperature detection units, a first isolator, a second isolator, a third isolator, a first signal output circuit, and a second signal output circuit. Each voltage detection unit is connected to the first signal output circuit through the first isolator, and each temperature detection unit is connected to the second signal output circuit through the second and third isolators. Each voltage detection unit includes a voltage detector, a first amplifier, and a fourth isolator connected in sequence, with the voltage detector connected to the positive and negative terminals of a single battery cell. Each temperature detection unit includes a temperature sensor, a voltage comparator, and a second amplifier connected in sequence, with the temperature sensor used to detect the temperature of a single battery cell. This utility model achieves pure hardware protection, without relying on software, and meets the withstand voltage requirements of relevant rail transit standards through multi-stage isolators.

Description

Technical Field

[0001] This utility model belongs to the field of battery protection circuit technology, and in particular relates to a battery hardware protection circuit and a power battery. Background Technology

[0002] To achieve electrification, rail transit systems are equipped with power battery systems. To improve the reliability of these systems, software-based protection mechanisms are typically used. If the software fails, the power battery system cannot be protected. Furthermore, according to relevant rail transit standards (e.g., AC5600V / min or DC7918V / min), the power battery system requires both highly reliable protection mechanisms and high voltage withstand capabilities, while minimizing the impact on the system during implementation.

[0003] Therefore, there is an urgent need to design a pure hardware redundant protection circuit that can ensure the safety of the power battery system when the software protection mechanism fails, while also meeting the withstand voltage requirements in relevant rail transit standards. Utility Model Content

[0004] The purpose of this utility model is to provide a battery hardware protection circuit and a power battery to solve the problem that the protection mechanism determined by software cannot protect the power battery system when it fails, and to meet the withstand voltage requirements in relevant rail transit standards.

[0005] This utility model solves the above-mentioned technical problems through the following technical solution: a battery hardware protection circuit, including multiple voltage detection units, multiple temperature detection units, a first isolator, a second isolator, a third isolator, a first signal output circuit, and a second signal output circuit; the output terminal of each voltage detection unit is connected to the first signal output circuit through the first isolator, and the output terminal of each temperature detection unit is connected to the second signal output circuit in sequence through the second isolator and the third isolator;

[0006] Each voltage detection unit corresponds to a single cell. Each voltage detection unit includes a voltage detector, a first amplifier, and a fourth isolator connected in sequence. The input terminal of the voltage detector is connected to the positive and negative terminals of the corresponding single cell.

[0007] Each temperature detection unit corresponds to a single battery cell. Each temperature detection unit includes a temperature sensor, a voltage comparator, and a second amplifier connected in sequence. The temperature sensor is used to detect the temperature of the corresponding single battery cell.

[0008] The battery hardware protection circuit of this invention is a purely hardware circuit that can generate corresponding overvoltage or overtemperature signals when the battery experiences overvoltage or overtemperature, achieving battery protection without relying on any software. Simultaneously, both voltage and temperature detection are achieved through two-stage isolation, capable of withstanding AC5600V withstand voltage surges, meeting the withstand voltage requirements of relevant rail transit standards. Multiple voltage detection units share a single first isolator and a first signal output circuit, while multiple temperature detection units share a single second isolator, a third isolator, and a second signal output circuit, significantly reducing circuit space and cost.

[0009] Furthermore, the battery hardware protection circuit also includes a power module, which includes a DC power supply, a first DC-DC converter, and a second DC-DC converter connected in sequence. The input terminal of the DC power supply is connected to an external power source. The output voltage of the first DC-DC converter is used to power the secondary side of the fourth and second isolators, and the primary side of the first and third isolators. The output voltage of the second DC-DC converter is used to power the temperature detection unit and the primary side of the second isolator. The DC power supply is used to power the secondary side of the first and third isolators, the first signal output circuit, and the second signal output circuit.

[0010] Only the input terminal of the voltage detector consumes battery power, which has little impact on the protected battery. While minimizing the impact on the protected battery, it ensures that the withstand voltage requirements in the relevant standards are met.

[0011] Furthermore, the first isolator, the second isolator, the third isolator, and the fourth isolator are all opto-isolators.

[0012] Furthermore, the temperature sensor is a thermistor with a negative temperature coefficient, and the thermistor is attached to the corresponding single cell.

[0013] Furthermore, both the first signal output circuit and the second signal output circuit include a third amplifier, a diode, and a relay; the output terminal of the third amplifier is connected to the coil of the relay, and the diode is connected in parallel across the two ends of the coil of the relay.

[0014] The output signal of the first or third isolator is amplified by the third amplifier so that the output signal can drive the relay to operate; the diode acts as a freewheeling diode to discharge the coil current of the relay, thus preventing the coil current of the relay from impacting the third amplifier and damaging it.

[0015] Based on the same concept, this utility model also provides a power battery, which includes the battery hardware protection circuit described above.

[0016] Compared with the prior art, the advantages of this utility model are:

[0017] The battery hardware protection circuit provided by this utility model adopts a pure hardware structure and does not rely on any software. It can realize the protection of the battery when it is over-voltage or over-temperature. At the same time, it also meets the withstand voltage requirements in the relevant standards of rail transit through multi-stage isolators.

[0018] This invention requires only a low power consumption for the voltage detector, while other circuits are powered by a power module, minimizing the impact on the protected battery and ensuring that the withstand voltage requirements in relevant standards are met. Attached Figure Description

[0019] To more clearly illustrate the technical solution of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a structural block diagram of the battery hardware protection circuit in an embodiment of this utility model;

[0021] Figure 2 This is a circuit diagram of the voltage detection unit in an embodiment of this utility model;

[0022] Figure 3 This is a schematic diagram of the first isolator and the first signal output circuit in an embodiment of this utility model;

[0023] Figure 4 This is a circuit diagram of the temperature detection unit in an embodiment of this utility model;

[0024] Figure 5 This is a circuit diagram of the second isolator in an embodiment of this utility model;

[0025] Figure 6 This is a schematic diagram of the third isolator and the second signal output circuit in an embodiment of this utility model. Detailed Implementation

[0026] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0027] like Figure 1As shown, the battery hardware protection circuit provided in this embodiment includes multiple voltage detection units, multiple temperature detection units, a first isolator U3, a second isolator U5, a third isolator U6, a first signal output circuit, and a second signal output circuit. The output terminal of each voltage detection unit is connected to the first signal output circuit through the first isolator U3, and the output terminal of each temperature detection unit is connected to the second signal output circuit through the second isolator U5 and the third isolator U6 in sequence. Each voltage detection unit corresponds to a single battery cell, and each voltage detection unit includes a voltage detector U1, a first amplifier V1, and a fourth isolator U2 connected in sequence. The input terminal of the voltage detector U1 is connected to the positive and negative terminals of the corresponding single battery cell. Each temperature detection unit corresponds to a single battery cell, and each temperature detection unit includes a temperature sensor, a voltage comparator U4, and a second amplifier V2 connected in sequence. The temperature sensor is used to detect the temperature of the corresponding single battery cell.

[0028] A power battery consists of multiple individual cells, which are typically connected in series, meaning the negative terminal of one cell is connected to the positive terminal of the next. The negative terminals of all cells are not shared. Therefore, each cell corresponds to a voltage detection unit, and all voltage detection units share a first isolator U3 and a first signal output circuit. The voltage detection unit detects whether the corresponding cell has an overvoltage condition. If an overvoltage condition is detected, the fourth isolator U2 and the first isolator U3 are activated, and the first signal output circuit generates an overvoltage signal.

[0029] Each individual battery cell corresponds to a temperature detection unit. The temperature detection unit does not consume the current of the individual battery cell. All temperature detection units share a second isolator U5, a third isolator U6, and a second signal output circuit. All temperature sensors share a common ground. The temperature detection unit detects whether the corresponding individual battery cell has over-temperature phenomena. When an over-temperature phenomenon occurs, it drives the second isolator U5 and the third isolator U6, and the second signal output circuit generates an over-temperature signal.

[0030] In a specific embodiment of this utility model, the battery hardware protection circuit further includes a power supply module. The power supply module includes a DC power supply, a first DC-DC converter, and a second DC-DC converter connected in sequence. The input terminal of the DC power supply is connected to an external power source. The 5V output voltage of the first DC-DC converter is used to power the secondary side of the fourth isolator U2 and the second isolator U5, and the primary side of the first isolator U3 and the third isolator U6. The 5V output voltage of the second DC-DC converter is used to power the temperature detection unit and the primary side of the second isolator U5. The 24V output voltage of the DC power supply is used to power the secondary side of the first isolator U3 and the third isolator U6, the first signal output circuit, and the second signal output circuit.

[0031] Only the voltage detection unit consumes the current of a single battery cell; the power for other parts comes from the power module, minimizing the impact on the protected battery and reducing battery current consumption. The static power consumption of a single voltage detection unit is less than 2uA (5uW). The first DC-DC converter is connected in parallel with either the first isolator U3 or the third isolator U6, and the second DC-DC converter is connected in parallel with the second isolator U5. When they are connected in parallel, the minimum isolation voltage between the two isolators is taken as the final isolation voltage. When the isolation voltages of the first isolator U3 to the fourth isolator U2, the first DC-DC converter, and the second DC-DC converter are all DC 5000V, the two-stage isolation meets the withstand voltage requirements of relevant rail transit standards (AC 5600V / min or DC 7918V / min). This invention ensures compliance with relevant standards' withstand voltage requirements while minimizing battery power consumption.

[0032] In a specific embodiment of this utility model, the first isolator U3, the second isolator U5, the third isolator U6 and the fourth isolator U2 are all opto-isolators, and the model of the opto-isolator is EL1019(TA)-VG.

[0033] In a specific embodiment of this utility model, such as Figure 2 As shown, the input terminal of voltage detector U1 is connected to the positive and negative terminals of a single battery cell, and the output terminal of voltage detector U1 is connected to the primary side of the fourth isolator U2 through the first amplifier V1; Figure 3 As shown, the secondary side of the fourth isolator U2 is connected to the primary side of the first isolator U3, and the secondary side of the first isolator U3 is connected to the first signal output circuit. The output voltage 5V_ISO of the first DC-DC converter supplies power to the secondary side of the fourth isolator U2 and the primary side of the first isolator U3, without consuming the current of a single battery cell.

[0034] Under normal circumstances, the voltage of a single battery cell is generally below 3.8V. When a single battery cell is overcharged or malfunctions, causing the voltage to rise to 4.0±0.1V, the output signal of the first amplifier V1 drives the fourth isolator U2, which in turn drives the output signal of the first isolator U3 to drive the relay K1 in the first signal output circuit. The contacts of the relay K1 open. When the contacts of the relay K1 are connected in series with the main circuit of the power battery, the main circuit of the power battery is cut off, thus achieving protection.

[0035] Multiple voltage detection units share a first isolator U3 and a first signal output circuit. When any voltage detection unit detects that the corresponding single battery cell is overcharged or an abnormality occurs causing the voltage to rise, it will drive the first isolator U3, and then drive the relay K1 in the first signal output circuit, so that the contacts of the relay K1 change from normally closed to open.

[0036] In a specific embodiment of this invention, the temperature sensor of each temperature detection unit is a negative temperature coefficient thermistor (NTC). The thermistor is attached to the corresponding individual battery cell and used to detect the temperature of the individual battery cell. Figure 4 As shown, the thermistor and resistor R26 divide the output voltage V5H of the second DC-DC converter, which then serves as the input to voltage comparator U4. The output of voltage comparator U4 is connected to the second amplifier V2. Figure 5 and Figure 6 As shown, the output of the second amplifier V2 is connected to the primary side of the second isolator U5, the secondary side of the second isolator U5 is connected to the primary side of the third isolator U6, and the secondary side of the third isolator U6 is connected to the second signal output circuit. Figure 4 , Figure 5 and Figure 6 All are powered by the power module and do not consume the current of individual batteries. V24 is the output voltage of the DC power supply, V5_ISO is the output voltage of the first DC-DC converter, and V5H is the output voltage of the second DC-DC converter.

[0037] Under normal circumstances, the cell temperature of a single battery cell is generally below 60℃. When a single battery cell overheats or malfunctions, causing the temperature to rise to 70±2℃, the output signal of the second amplifier V2 drives the second isolator U5, which in turn drives the output signal of the third isolator U6 to drive the relay K2 in the second signal output circuit. The contacts of relay K2 open. When the contacts of relay K2 are connected in series with the main circuit of the power battery, the main circuit of the power battery is cut off, thus achieving protection.

[0038] Multiple temperature detection units share a second isolator U5, a third isolator U6, and a second signal output circuit. When any temperature detection unit detects that the corresponding single cell is overheated or an abnormality causes the temperature to rise, it will drive the second isolator U5 and the third isolator U6, and then drive the relay K2 in the second signal output circuit, so that the contacts of the relay K2 change from normally closed to open.

[0039] like Figure 3 As shown, the first signal output circuit includes a third amplifier V3, a diode D1, and a relay K1. The output terminal of the third amplifier V3 is connected to the coil of the relay K1, and the diode D1 is connected in parallel across the coil of the relay K1. The third amplifier V3 amplifies the output signal of the first isolator U3, enabling the output signal to drive the relay K1. The diode D1 acts as a freewheeling diode, discharging the coil current of the relay K1 to prevent the coil current of the relay K1 from impacting the third amplifier V3 and damaging it.

[0040] like Figure 6As shown, the second signal output circuit includes a third amplifier V4, a diode D2, and a relay K2. The output terminal of the third amplifier V4 is connected to the coil of the relay K2, and the diode D2 is connected in parallel across the coil of the relay K2. The third amplifier V4 amplifies the output signal of the third isolator U6, enabling the output signal to drive the relay K2. The diode D2 acts as a freewheeling diode, discharging the coil current of the relay K2 to prevent the coil current of the relay K2 from impacting the third amplifier V4 and damaging it.

[0041] The above description only discloses specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or modifications that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.

Claims

1. A battery hardware protection circuit, characterized in that: The battery hardware protection circuit includes multiple voltage detection units, multiple temperature detection units, a first isolator, a second isolator, a third isolator, a first signal output circuit, and a second signal output circuit; the output terminal of each voltage detection unit is connected to the first signal output circuit through the first isolator, and the output terminal of each temperature detection unit is connected to the second signal output circuit in sequence through the second isolator and the third isolator; Each voltage detection unit corresponds to a single cell. Each voltage detection unit includes a voltage detector, a first amplifier, and a fourth isolator connected in sequence. The input terminal of the voltage detector is connected to the positive and negative terminals of the corresponding single cell. Each temperature detection unit corresponds to a single battery cell. Each temperature detection unit includes a temperature sensor, a voltage comparator, and a second amplifier connected in sequence. The temperature sensor is used to detect the temperature of the corresponding single battery cell.

2. The battery hardware protection circuit according to claim 1, characterized in that: The battery hardware protection circuit also includes a power module, which includes a DC power supply, a first DC-DC converter, and a second DC-DC converter connected in sequence. The input terminal of the DC power supply is connected to an external power source. The output voltage of the first DC-DC converter is used to power the secondary side of the fourth and second isolators, and the primary side of the first and third isolators. The output voltage of the second DC-DC converter is used to power the temperature detection unit and the primary side of the second isolator. The DC power supply is used to power the secondary side of the first and third isolators, the first signal output circuit, and the second signal output circuit.

3. The battery hardware protection circuit according to claim 1, characterized in that: The first isolator, the second isolator, the third isolator and the fourth isolator are all opto-isolators.

4. The battery hardware protection circuit according to claim 1, characterized in that: The temperature sensor is a negative temperature coefficient thermistor, which is attached to the corresponding individual battery cell.

5. The battery hardware protection circuit according to any one of claims 1 to 4, characterized in that: Both the first signal output circuit and the second signal output circuit include a third amplifier, a diode, and a relay; the output terminal of the third amplifier is connected to the coil of the relay, and the diode is connected in parallel across the two ends of the coil of the relay.

6. A power battery, characterized in that: The power battery includes a battery hardware protection circuit as described in any one of claims 1 to 5.

Images