Intelligent battery sensor adopting discrete device

Abstract

The utility model discloses an intelligent battery sensor using discrete devices, comprising a circuit board assembly PCBA and a diverter, the circuit board assembly PCBA comprises a power supply voltage acquisition voltage division circuit, a reference voltage circuit, a first-stage operational amplifier, a second-stage operational amplifier, an AD chip, an MCU and a power supply anti-reverse diode D1, the current detection end of the shunt is connected to the positive input end and the negative input end of the first-stage operational amplifier, the reference voltage circuit is connected to the output reference end of the first-stage operational amplifier, the reference voltage circuit is connected to the negative input end and the output reference end of the second-stage operational amplifier, the reference voltage circuit is connected to the negative input end of the differential input of the AD chip, and the output reference end of the differential input of the AD chip is connected to the output reference end of the second-stage operational amplifier. And the output of the first-stage operational amplifier is connected to the positive input end of the second-stage operational amplifier and the input of the AD chip. The current sampling circuit uses a two-stage operational amplifier circuit, and ensures that large current sampling does not exceed the range of AD acquisition and small current sampling has very high resolution and precision at the same time.

Description

Technical Field

[0001] This utility model relates to the field of battery sensor technology, specifically a smart battery sensor using discrete components. Background Technology

[0002] Intelligent battery sensors measure the battery's voltage, current, and temperature signals, and use algorithms to estimate the battery's state of charge (SOC), state of health (SOH), and state of function (SOF). These sensors then interact with the battery management system (BMS), engine control system (ECM), or other control systems via communication interfaces (such as the LIN bus). SOC, SOH, and SOF are well-known and crucial battery parameters, commonly used for battery charge and discharge control, health warnings, and start-up function prediction. They are particularly prevalent in vehicles with engine start-stop systems, serving as indispensable input parameters for engine start-stop control.

[0003] Most existing smart battery sensors use imported dedicated fully integrated chips. These chips integrate operational amplifiers, AD acquisition, programmable gain amplifiers (PGA), power modules, MCUs, LIN transceivers, etc., and are specifically developed for smart battery sensor applications. While highly integrated dedicated chips can simplify circuit board hardware design and allow for very small board sizes, their high complexity means there are no comparable alternatives in the short term, resulting in high prices, long supply cycles, and a significant risk of chip shortages. Furthermore, the chip parameters are fixed and cannot be modified or adjusted, making them unsuitable for adapting to the ever-changing customer needs and the diverse types of batteries. This is mainly reflected in:

[0004] 1. The MCU's memory is fixed and cannot be reduced to save costs, nor can it be expanded to integrate more complex algorithms and special functions required by customers (such as OTA backup and rollback).

[0005] 2. The communication interface is fixed to LIN bus and cannot be changed to other communication methods (such as CAN bus, PSI5 bus, SENT bus, etc.).

[0006] 3. The current sampling amplification factor and the upper and lower limits of PGA are fixed, and can only be matched with battery applications in a specific current range.

[0007] 4. The upper and lower limits of voltage acquisition are fixed and can only be matched with batteries with a specific voltage range (such as 12V batteries).

[0008] To address this, we propose a smart battery sensor employing discrete components. Utility Model Content

[0009] The purpose of this invention is to provide a smart battery sensor using discrete components to solve the problems in the prior art.

[0010] To achieve the above objectives, this utility model provides the following technical solution: A smart battery sensor using discrete components, comprising a circuit board assembly (PCBA) and a shunt. The PCBA includes a power supply voltage acquisition divider circuit, a reference voltage circuit, a first-stage operational amplifier (op-amp), a second-stage operational amplifier (op-amp), an analog-to-digital (AD) chip, an MCU, and a power supply reverse protection diode D1. The current detection terminals of the shunt are respectively connected to the positive and negative input terminals of the first-stage op-amp. The reference voltage circuit is connected to the output reference terminal of the first-stage op-amp. The reference voltage circuit is connected to the negative input terminal and the output reference terminal of the second-stage op-amp. The reference voltage circuit is connected to the negative input terminal of the differential input of the AD chip. The output of the first-stage op-amp is connected to the positive input terminal of the second-stage op-amp and the input of the AD chip. The output of the second-stage op-amp is connected to the input of the AD chip. The power supply voltage acquisition divider circuit is connected to the input of the AD chip. The output of the AD chip is connected to the MCU via an SPI interface. The power supply reverse protection diode D1 is connected to the power supply line.

[0011] Preferably, the MCU integrates a power supply chip LDO, a LIN communication transceiver, and a temperature sensor, and the MCU communicates with other devices through the LIN interface.

[0012] Preferably, the power supply voltage acquisition voltage divider circuit includes a voltage divider circuit composed of resistors R1 and R2, which divides the battery voltage and provides it to the input of the AD chip.

[0013] Preferably, the reference voltage circuit includes a voltage divider circuit composed of resistors R3 and R4, providing a stable reference voltage VREF_2V5 to the output reference terminal of the first-stage operational amplifier, the negative input terminal and output reference terminal of the second-stage operational amplifier, and the negative input terminal of the differential input of the AD chip.

[0014] Preferably, it also includes a battery negative terminal clamp, a load negative terminal grounding connection bolt, a housing body, and a housing cover. The circuit board assembly (PCBA) is connected to the shunt via pin soldering, and the circuit board assembly (PCBA) is connected to the housing body via pin soldering of connectors. The shunt is connected to the battery negative terminal clamp via resistance welding or metal riveting. The shunt is connected to the load negative terminal grounding connection bolt via resistance welding or metal riveting.

[0015] Preferably, the connector's pins include a power positive pin and a communication pin, with the power positive pin connected to the battery's positive terminal.

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

[0017] The current sampling circuit uses a two-stage operational amplifier circuit, which ensures that large current sampling does not exceed the range of AD acquisition and that small current sampling has high resolution and accuracy.

[0018] VREF_2V5 is used as the negative input terminal for differential amplification and differential AD acquisition, and also as the reference voltage for the outputs of the first and second stage op-amps. This fundamentally eliminates the errors introduced by the deviation and jitter of VREF_2V5, resulting in higher current sampling accuracy. It also reduces the accuracy and ripple requirements of VREF_2V5, avoiding the need for expensive high-precision, low-ripple voltage reference sources; a common regulated power supply can meet the requirements, thus reducing system cost. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic diagram of the structure of this utility model;

[0021] Figure 2 This is the circuit diagram of the PCBA (Printed Circuit Board Assembly) of this utility model.

[0022] In the diagram: 1. Battery negative terminal clamp; 2. Load negative terminal grounding connection bolt; 3. Shunt; 4. Circuit board assembly (PCBA); 5. Housing body; 6. Housing cover. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model.

[0024] Please see Figure 1-2In this embodiment of the present invention, an intelligent battery sensor employing discrete components includes a circuit board assembly (PCBA) 4 and a shunt 3. The circuit board assembly (PCBA) 4 includes a power supply voltage acquisition divider circuit, a reference voltage circuit, a first-stage operational amplifier (op-amp), a second-stage operational amplifier (op-amp), an analog-to-digital (ADC) chip, an MCU, and a power supply reverse protection diode (D1). The current detection terminals of the shunt 3 are respectively connected to the positive and negative input terminals of the first-stage op-amp. The reference voltage circuit is connected to the output reference terminal of the first-stage op-amp, the negative input terminal and the output reference terminal of the second-stage op-amp, and the negative input terminal of the differential input of the ADC chip. The output of the first-stage op-amp is connected to the positive input terminal of the second-stage op-amp and the input of the ADC chip. The output of the second-stage op-amp is connected to the input of the ADC chip. The power supply voltage acquisition divider circuit is connected to the input of the ADC chip. The output of the ADC chip is connected to the MCU via an SPI interface. The power supply reverse protection diode (D1) is connected to the power supply line.

[0025] The MCU integrates a power supply chip LDO, a LIN communication transceiver, and a temperature sensor. The MCU communicates with other devices through the LIN interface.

[0026] The power supply voltage acquisition and voltage divider circuit includes a voltage divider circuit composed of resistors R1 and R2, which divides the battery voltage and provides it to the input terminal of the AD chip.

[0027] The reference voltage circuit includes a voltage divider circuit composed of resistors R3 and R4, providing a stable reference voltage VREF_2V5 to the output reference terminal of the first-stage operational amplifier, the negative input terminal and output reference terminal of the second-stage operational amplifier, and the negative input terminal of the differential input of the AD chip.

[0028] It also includes a battery negative terminal clamp 1, a load negative terminal grounding connection bolt 2, a housing body 5, and a housing cover 6. The circuit board assembly 4 is connected to the shunt 3 by PIN soldering, and the circuit board assembly 4 is connected to the housing body 5 by connector PIN soldering. The shunt 3 is connected to the battery negative terminal clamp 1 by resistance welding or metal riveting. The shunt 3 is connected to the load negative terminal grounding connection bolt 2 by resistance welding or metal riveting. The connector PIN includes a power positive PIN and a communication PIN, and the power positive PIN is connected to the battery positive terminal.

[0029] The current from electrical equipment enters the shunt through the ground wire, and after flowing through the shunt, it returns to the negative terminal of the battery via clamps. The shunt is usually designed with a precision resistor, and the magnitude and direction of the current can be determined by measuring the voltage drop across the precision resistor.

[0030] A connector typically includes a power positive pin and a communication pin. The power pin is connected to the positive terminal of the battery, and the communication pin can be a single pin (e.g., LIN bus, PSI5 bus, SENT bus) or two pins (e.g., CAN bus). This invention uses a LIN communication interface with a single communication pin as an example.

[0031] The PCBA assembly solution of this invention abandons the use of imported dedicated fully integrated chips and is built using discrete components, thereby avoiding the shortcomings of the original technical solution and having the following technical effects:

[0032] The MCU used is a general-purpose integrated MCU in the industry. The parameters such as communication method, computing power and memory size can be flexibly selected according to the actual application requirements, which can meet customer needs and reduce costs. For example, if the customer's functional requirements are simpler and do not require OTA backup and rollback, a chip with a small memory (generally 48k is sufficient) can be selected; conversely, a chip with a larger memory (such as 64k, 128k, 256k or even 1M) can be selected.

[0033] In addition to the integrated chip shown in the example above, more general-purpose MCU models can also be selected, along with suitable power dispensing devices (LDOs), communication interfaces, and temperature sensors. Furthermore, the transceiver for the communication interface can be flexibly selected according to customer needs, such as LIN transceivers, CAN transceivers, PSI5 transceivers, SENT transceivers, etc.

[0034] Furthermore, by selecting operational amplifiers with different amplification factors or AD chips with different PGA amplification factors, the current sampling range can be flexibly adjusted to match battery applications with different current ranges, such as ±300A, ±600A, ±1000A, ±1500A, etc.

[0035] Finally, by adjusting the voltage divider resistors on the power supply voltage acquisition circuit, the upper and lower limits of voltage acquisition can be flexibly adjusted to match batteries with different voltage ranges (such as 12V, 24V, 48V, etc.).

[0036] The main functions of the battery sensor described in this invention and its implementation method are as follows:

[0037] 1) Reference Voltage Generation: The LDO inside the highly integrated MCU chip is used to reduce the power supply voltage to a 5V regulated output (VCC_5V) as the working power supply for the AD acquisition chip. At the same time, the voltage is further reduced to a 2.5V regulated output (VREF_2V5) through voltage divider through resistors R3 and R4. This voltage is used as the output reference voltage of the first and second stage operational amplifier circuits and the input reference voltage of the second stage operational amplifier circuit. It is also connected to the acquisition port of the AD acquisition chip as the negative input reference voltage for differential acquisition.

[0038] 2) Power supply voltage acquisition: Before the power supply anti-reverse diode, the power supply voltage is divided by resistors R1 and R2 to reduce it to the range of 0-5V, and then connected to the AD chip for acquisition.

[0039] 3) Shunt Current Acquisition: The weak bidirectional voltage signal generated after the current flows through the precision resistor of the shunt is input to the positive and negative input terminals of the first-stage operational amplifier circuit. After amplification, it outputs a differential voltage relative to VREF_2V5. This output voltage is input to the differential positive input terminal (negative input terminal is VREF_2V5) of the AD chip for acquisition as a large current sample. Simultaneously, this output voltage is input to the positive input terminal of the second-stage operational amplifier circuit, forming a differential input with the negative input terminal VREF_2V5 and undergoing second-stage amplification. After second-stage amplification, the output is a differential voltage relative to VREF_2V5, which is then input to the differential positive input terminal (negative input terminal is VREF_2V5) of the AD chip for acquisition as a small current sample. Regardless of whether it is a large current sample or a small current sample, the AD acquisition chip can also dynamically adapt the AD acquisition range to the current value by setting different PGA gains, ensuring optimal resolution and accuracy.

[0040] The above-mentioned scheme, which uses first-stage and second-stage operational amplifier circuits, ensures that large current sampling does not exceed the range of AD acquisition and that small current sampling has high resolution and accuracy, which is the core innovation of this invention.

[0041] Furthermore, using VREF_2V5 as the negative input terminal for differential amplification and differential AD acquisition, and simultaneously using VREF_2V5 as the reference voltage for the outputs of the first and second stage operational amplifiers, is another core innovation of this invention. This scheme fundamentally eliminates the errors introduced by the deviation and jitter of VREF_2V5, resulting in higher accuracy in current sampling. It also reduces the accuracy and ripple requirements of VREF_2V5, avoiding the use of expensive high-precision, low-ripple voltage reference sources; ordinary regulated power supplies can meet the requirements, thus reducing system costs.

[0042] 4) Temperature acquisition: directly use the temperature sensor inside the MCU chip.

[0043] 5) Battery Status Monitoring: The MCU communicates with the AD acquisition chip via SPI to obtain sampled voltage and current values. Combined with temperature signals from the chip's internal temperature sensor, relevant algorithms for SOC, SOH, and SOF are run to obtain these battery status parameters, which are then transmitted via the LIN bus. The SOC, SOH, and SOF algorithms are mature algorithms in this field and will not be elaborated upon in this invention.

[0044] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A smart battery sensor employing discrete components, comprising a circuit board assembly (PCBA) (4) and a shunt (3), characterized in that: The circuit board assembly PCBA (4) includes a power supply voltage acquisition divider circuit, a reference voltage circuit, a first-stage operational amplifier, a second-stage operational amplifier, an AD chip, an MCU, and a power supply anti-reverse diode D1. The current detection terminal of the shunt (3) is connected to the positive and negative input terminals of the first-stage operational amplifier, respectively. The reference voltage circuit is connected to the output reference terminal of the first-stage operational amplifier. The reference voltage circuit is connected to the negative input terminal and the output reference terminal of the second-stage operational amplifier. The reference voltage circuit is connected to the negative input terminal of the differential input of the AD chip. The output of the first-stage operational amplifier is connected to the positive input terminal of the second-stage operational amplifier and the input of the AD chip. The output of the second-stage operational amplifier is connected to the input of the AD chip. The power supply voltage acquisition divider circuit is connected to the input of the AD chip. The output of the AD chip is connected to the MCU through the SPI interface. The power supply anti-reverse diode D1 is connected to the power supply line.

2. The intelligent battery sensor using discrete components according to claim 1, characterized in that: The MCU integrates a power supply chip LDO, a LIN communication transceiver, and a temperature sensor. The MCU communicates with other devices through the LIN interface.

3. The intelligent battery sensor using discrete components according to claim 1, characterized in that: The power supply voltage acquisition and voltage divider circuit includes a voltage divider circuit composed of resistors R1 and R2, which divides the battery voltage and provides it to the input terminal of the AD chip.

4. A smart battery sensor employing discrete components according to claim 1, characterized in that: The reference voltage circuit includes a voltage divider circuit composed of resistors R3 and R4, providing a stable reference voltage VREF 2V5 to the output reference terminal of the first-stage operational amplifier, the negative input terminal and output reference terminal of the second-stage operational amplifier, and the negative input terminal of the differential input of the AD chip.

5. A smart battery sensor employing discrete components according to claim 1, characterized in that: It also includes a battery negative terminal clamp (1), a load negative terminal grounding connection bolt (2), a housing body (5) and a housing cover (6). The circuit board assembly (PCBA) (4) and the shunt (3) are connected by PIN soldering. The circuit board assembly (PCBA) (4) and the housing body (5) are connected by PIN soldering of the connector. The shunt (3) and the battery negative terminal clamp (1) are connected together by resistance welding or metal riveting. The shunt (3) and the load negative terminal grounding connection bolt (2) are connected together by resistance welding or metal riveting.

6. A smart battery sensor employing discrete components according to claim 5, characterized in that: The connector's pins include a power positive pin and a communication pin, with the power positive pin connected to the battery's positive terminal.

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