With the rapid development of new geophysical technologies, the ultra multi-channel and ultra multi shot acquisition mode has gradually become the mainstream of field exploration projects. This means that the investment in equipment arrangement in field exploration projects will gradually increase, and the problem of lead-acid battery power supply is becoming increasingly prominent, especially in mountainous seismic exploration with harsh terrain, which has gradually become a bottleneck affecting the construction progress of field acquisition projects. In addition, during field seismic exploration operations, due to the wide distribution of construction and high mobility of construction personnel, there have always been various safety hazards caused by the loss, theft, and improper use of external portable power supply systems.
In recent years, in order to improve the efficiency of field construction and reduce labor costs, intelligent portable new energy battery power supply systems have gradually been valued as new power supply equipment for green exploration. Compared with lead-acid batteries, lithium iron phosphate batteries have the characteristics of light weight, small size, long service life, environmental protection, and safety. In order to facilitate unified management of various power supply systems, the Internet of Things and Internet technology can be combined to connect intelligent portable power supply systems to the “cloud”. Management personnel only need to access them on mobile terminals to view real-time location and working status information of each power supply system, So as to grasp the operation status of each device in a timely manner. With the continuous improvement of people’s awareness of environmental protection and safety, green exploration will inevitably become the mainstream of the world, and intelligent portable seismic equipment will gradually replace existing conventional old seismic equipment, leading a new wave of seismic exploration equipment trend.
1. Characteristics of lithium iron phosphate batteries
Today, with the rapid development of green new energy, the concepts of green, environmental protection, and safety have gradually been introduced into various fields. Seismic exploration equipment is also undergoing reforms towards lightweighting, miniaturization, and safety. New types of geophysical equipment can improve construction efficiency, reduce construction costs, and have a wide range of application prospects and market value. Table 1 shows the comprehensive performance comparison between lead-acid batteries and lithium iron phosphate batteries.
| Number | Battery type | Lead-acid battery | Portable power supply |
| 1 | Positive electrode | Lead dioxide | Lithium iron phosphate |
| 2 | Negative electrode | Sponge like lead | Carbon materials |
| 3 | Electrolyte | Dilute sulfuric acid solution | Polymer electrolyte |
| 4 | Single cell voltage (V) | 2 | 3.2 |
| 5 | Weight specific energy (Wh/kg) | 30-50 | 100-150 |
| 6 | Volume specific energy (Wh/L) | 60-90 | 200-250 |
| 7 | Number of cycles (times) | 300~500 | 2000 |
| 8 | Monthly self discharge rate | 4-5% | ＜ 3% |
| 9 | Working temperature (℃) | Charging: 5-45 Discharge:~20~45 | Charging: 0-55 Discharge:~20-70 |
| 10 | Harmful substances | Lead | Free |
| 11 | Environmental friendliness | Pollution | Environmental friendliness |
| 12 | Whether there is a memory effect or not | Yes | No |
| 13 | Energy density | Low | High |
| 14 | Protection circuit | Yes | No |
| 15 | Service life (years) | 2-3 | 7-8 |
| 16 | Charging time (h) | 7-10 | 6-7 |
| 17 | 60AH battery weight (kg) | 18.4 | 8.9 |
1.1 Long lifespan
The number of charge and discharge cycles for lead-acid batteries is approximately 300-500 times, with a service life of approximately 2 years, while lithium iron phosphate batteries can have a maximum charge and discharge cycle of over 2000 times, with a service life of 7-8 years.
1.2 Lightweight and miniaturization
The volume of lithium iron phosphate batteries with the same specifications and capacity only accounts for about two-thirds of lead-acid batteries, while the weight only accounts for about one-third of lead-acid batteries. This obvious advantage enables the relocation of field collection and construction equipment to save more human resources, reduce relocation time, improve field construction efficiency, and shorten construction cycles.
1.3 Environmental Protection and Safety
Due to the presence of a large amount of lead in lead-acid batteries, if the batteries are not professionally disposed of after use, it is likely to cause serious environmental pollution. The main material in lithium batteries is lithium, which is globally recognized as a green and environmentally friendly material and will not cause pollution to the environment during production or use.
Considering the actual situation of field seismic exploration, lithium iron phosphate batteries are also more suitable for field construction use than lead-acid batteries. It not only has the characteristics of lightweight and environmentally friendly lithium batteries, but also takes into account the advantages of flame and explosion prevention.
1.4 No memory effect
If lead-acid batteries are operated for a long time when fully charged but not fully discharged, the battery capacity will gradually decrease below the rated capacity value, which is the memory effect of the battery. However, lithium iron phosphate batteries have no memory effect, which allows them to be charged and used at any time regardless of their state, making them more conducive to field construction and production.
2. Design scheme for intelligent power supply system
To avoid the loss and damage of external portable power supply systems, as well as to consider the complex working environment of field construction. The intelligent power supply system plans to use a dual-mode dual frequency positioning technology method of “Global Positioning System (GPS)+Beidou Satellite Navigation System (BDS)” to achieve precise positioning. At the same time, electric quantity monitoring and temperature monitoring sensors will be added to the power supply system to monitor its operating status. A smartphone application based on the Android platform will be developed at the monitoring terminal, which will be connected to the cloud through local operator networks or local WIFI networks, By doing so, real-time information such as the location and operational status of the portable power supply system can be obtained, enabling 24-hour monitoring of field equipment and reducing the consumption of human resources.
2.1 Overall System Framework
The overall framework of the system is mainly composed of a mobile monitoring terminal APP, a data cloud server, and a power management system. The entire system is designed with stability, security, flexibility, and efficiency as its design goals, and adopts advanced and mature technology to make the system more reliable, practical, and unique. Introducing centralized and decentralized management models, adopting the combination of Internet of Things and Internet technology, and utilizing cloud data processing architecture combined with mobile solutions, we strive to simplify human resource consumption to the greatest extent possible and provide convenient and flexible device supervision modes for management personnel. This design scheme mainly focuses on three aspects: power management, data transmission, and mobile monitoring terminals, and designs a portable power management system with autonomous positioning, remote data monitoring, and intelligent control.
2.2 Power Management Plan
In this scheme, a low-power microcontroller STM32F103 is mainly used as the main control center, and a 12 bit resolution analog-to-digital converter (ADC) integrated inside the chip is used to monitor the system battery level and obtain internal battery level information [2]. At the same time, temperature sensors are used to monitor the internal operating temperature of the system. When the current battery level exceeds or falls below the normal usage range or the operating temperature is too high during operation, the power should be turned off in a timely manner to protect the system and upload its status information. In response to the issues of loss and theft that may occur when such devices are used in the wild, we plan to add a positioning function inside the equipment.
At present, the existing field positioning solutions mainly use two methods: base station positioning and GPS positioning. Both of these methods have certain drawbacks for complex outdoor environments: on the one hand, positioning accuracy is affected by satellite signals; On the other hand, the influence of base station distance leads to significant errors. In view of this, this scheme proposes a dual mode positioning method based on BDS/GPS, which simultaneously receives satellite signals from two satellite navigation systems for combined positioning, thereby further improving its positioning accuracy.
2.3 Data transmission scheme
In terms of communication, the current mainstream wireless data transmission solutions mainly include wireless network (WiFi), ZigBee protocol (ZigBee), Lora communication technology (Lora), General Wireless Packet Service (GPRS) and other data transmission solutions. WiFi and ZigBee are mainly suitable for short distance wireless communication scenarios. Although LoRa can transmit up to 3-8KM, it needs to deploy separate network communication base stations during use, At the same time, as the number of deployment nodes increases, there is a certain degree of spectral interference between them. GPRS technology utilizes the wireless structure of the Global System for Mobile Communications (GSM) system, which has a wide network coverage and can be stably and continuously online, effectively solving the problem of remote data exchange in sensor networks. According to the design requirements, the data uploaded by the system mainly consists of physical location coordinate information, system operation status information, and related instructions with relatively small transmission volume, and there is no high requirement for transmission speed. Therefore, GPRS technology is adopted as the main communication method to transmit data to the network cloud.
2.4 Mobile monitoring terminal scheme
In recent years, with the rapid development of cloud computing technology, cloud computing has been widely applied in various industries. In order to facilitate users to obtain real-time monitoring information, the remote monitoring system is based on the Alibaba Cloud platform.
The Alibaba Cloud ECS server is a cloud server based on the Alibaba Cloud Feitian operating system. It adopts a distributed architecture with high concurrency processing capabilities and can provide elastic and scalable computing services according to user needs. Deploy the Windows operating system in the Alibaba Cloud backend, install the Java environment, and open server access ports.
The mobile end uses smartphones or tablets on the Android platform as monitoring clients, and develops app software based on the C/S architecture to monitor battery status and position on the platform. The App software mainly includes network module, database module, status display and position display module, and alarm module. The network module communicates with the cloud server using the HTTP protocol, and develops a client data acquisition interface based on the open communication interface of the cloud server. The database module is mainly used to store the obtained power related data information. Due to the small amount of data, this solution adopts a lightweight and easy to run SQLite database on the Android end. The status display module provides users with a friendly interactive interface to display the current power operation status. The location display module provides the user with current location information and displays the location of each power source to the user through a map. The drawing of the map in this scheme is achieved by embedding the Baidu Map module. The alarm module is used to alert management personnel for on-site maintenance through sound and vibration when the battery level is too low or the power supply is running abnormally.
3. Field testing
Conduct a 7-day study on the portable power supply system designed in this article
Three dimensional three component field testing.
3.1 Test content
Test content one: Compare the portable power supply system and 80AH lead-acid battery in field production, with testing parameters including charging test, discharge test, and channel capacity test.
Test content 2: Test the time required for the portable power system and 80AH lead-acid battery to charge from 10% to 100%, as well as the battery life to consume from 100% to 10%.
3.2. Testing methods and results
Test Method 1: The portable power supply system and 80AH lead-acid battery were tested on a three-dimensional project three component field with 16 three component 428DSU3 each. The portable power supply system with 16 428DSU3 took 60 hours, and the power consumption decreased from 100% to 10%, and the power was charged from 10% to 100%. The required time was 4-6 hours; It takes 48 hours for an 80AH lead-acid battery with 16 428DSU3 batteries, and the power is consumed from 100% to 10%, and charged from 10% to 100%. The required time is 7 to hours.
Test Method 2: The portable power supply system and 60AH lead-acid battery were tested at a three component field G crossover station in a three-dimensional project. The portable power supply system worked stably for 36 hours, while the 60AH lead-acid battery could only work stably for 8 hours.
Test method three: The portable power supply system and 60AH lead-acid battery were tested on a three-dimensional project three component field site, with 40 428 acquisition stations arranged along the Yangtze River. The portable power supply system worked stably for 144 hours, while the 60AH lead-acid battery could only work stably for 24 hours.
The test results are shown in Table 2.
| Battery type | Charging time (h) | 3D project power station with 16 428DSU3 | 3D project to G intersection station | 3D project power station with 40 428FDUs | Weight/kg |
| Intelligent portable power supply | 6 | 60 | 36 | 144 | 9.2 |
| Lead acid battery 80AH | 8 | 48 | / | / | 20 |
| Lead acid battery 60AH | 6 | / | 8 | 24 | 18.4 |
4. Conclusion
In today’s world where labor costs continue to rise and exploration investment continues to compress, traditional geophysical equipment is no longer sufficient for high-density exploration in increasingly complex terrains, and has even become a burden for field acquisition and construction. The research and development of intelligent portable power supply systems comply with the requirements of the world for new energy, green, environmental protection, and lightweight geophysical equipment, further expanding the potential for the development of geophysical equipment. Intelligent seismic exploration equipment is a new type of seismic instrument that integrates cutting-edge technologies such as the Internet, Internet of Things, new communication technology, and cloud technology. It represents a low-cost, high-efficiency, green, safe, and environmentally friendly field construction method, and will inevitably become the mainstream of future geophysical equipment development, making further contributions to the development of seismic exploration.