0 introduction
Energy tension and climate change have received attention to electric vehicles with energy-saving and environmentally friendly advantages. Electric cars use clean energy electrical energy as a long-term solution for future transportation [1]. For personal users, it is necessary to charge the close-up charging station or charging pile when charging, and the charging time is longer, such as selecting battery fast charge, the battery is large. If the battery is not enough in the current car and the time is tight, you need to replace the standby battery at any time. Electric vehicle batteries are large, not easy to operate, such as personal purchase of spare batteries will cause an increase in personal infrastructure, causing electric vehicles to be universal in personal users. Therefore, multiple batteries are often prepared by the charging station or battery rental company, and the battery is charged and maintained by the company, and the battery is replaced according to the requirements. Electric vehicle power supplements are mainly convertible.
This method has the following advantages: reducing the user's basic input; extending battery life; increasing battery utilization; helps to solve an emergency in the charging network; rental company uses Feng Valley electricity to charge, which is conducive to the overall grid Formation, etc. Due to the use of the power transmission mode, the battery will circulate between multi-user multi-region, and the battery is based on the battery condition when the battery is replaced, so the electric vehicle battery needs to be hooked with different users (such as license plate numbers, etc.). On the one hand, it is necessary to ensure that the user's personal information is not leaked; on the other hand, it is necessary to ensure that the battery is safe when the battery is used. At this point, the personnel of battery assets (such as charging stations or battery rental companies) are greatly improved for electric vehicle battery management.
This article combines the ESAM security module to the RF module to form a new security module RF transceiver, mount it in an electric vehicle battery, and set the handheld terminal with the ESAM security module. At this point, store the user's personal information and the battery's asset information in the ESAM security module, not only personal information is encrypted, but also when charging or electrifying, the battery is also required to ESAM security modules and intelligent grids in the battery. The background sales system is carried out, and the charge can be carried out normally, thereby ensuring the safety of battery assets.
1 system structure
In order to achieve electric vehicle battery management, the entire system is divided into the following parts: electric vehicle battery side battery safety RFID module, handheld, fixed read head, background management system.
Install a battery safety RFID module on an electric vehicle battery, referred to as a battery module. The module is used to implement battery information storage, data add-on, data interaction, etc., mainly composed of MCU, ESAM, and RF transmit RF transceivers. The system organizational structure is shown in Figure 1.
2 battery-side battery safety RFID module
2.1 ESAM Security Module
ESAM (Enbedded Secure Access Module) Embedded Security Control Module is an embedded security product with a dedicated high-performance security microprocessor for hardware platform, an internal independent on-screen operating system (COS), in addition to anti-test In addition to hardware features such as anti-attack, self-destructive, there is also a safe file key management and perfect security mechanism, and the characteristics of standard add-on-de-firing function. The internal structure includes a microprocessor, an encrypted coprocessor, a true random number generator, a ROM, RAM, EEPROM, and data I / O port [2].
Since the ESAM security module has the above security characteristics, the key data of the electric vehicle battery is stored in the ESAM module. Sort management for different battery data, set to transparent files or opaque files, that is, whether data communication is encrypted.
2.2 Main control MCU role
On the battery module, select the appropriate microcontroller as the MCU, currently the module selects the STM32 chip as the MCU, including a plurality of peripheral interfaces, can simultaneously connect the BMS system of the car itself, the ESAM security module, and RF transmit RF transceivers can be implemented. Data interaction between multiple modules while protocol the data in data interactions.
2.3 RF transceiver
The RF transceiver on the battery module is connected to the MCU through the SPI interface. At the same time, the same RF transceiver is configured on the handheld side, and the two wireless communication frequencies can be implemented.
At the same time, since the RF transceiver can implement multiple labels simultaneously, the fixed wireless communication read head can also be set in the door of the battery management warehouse to facilitate the storage of the warehouse.
3 handheld / fixed read head
The handset / fixed read head is a device read and written to the battery module. It is different from the handset as a mobile reading and writing device, mainly used to carry out the traum bank in the warehouse in the warehouse. , Including peripheral assistance such as display, keyboard, and human machine interactive system, which is convenient for operator applications. The fixed read head is mainly used for fixed locations such as warehouse access library. The RF transceiver can achieve multiple labels simultaneously read, and the features of the background processing are quickly done.
There is an optional GPRS module on the handset, which can be updated with the background primary station after handset collection information. For critical data, encryption is performed when transferring through the GPRS public network, so as not to intercept or tamper with others during public network transmission [3].
The PSAM card is required to be configured in the handheld or fixed read head equipment terminal, the PSAM card, the Purchase Secure Access Module, for merchants POS, network terminal, linear terminal, etc., responsible Machine safety control [4]. The PSAM card is distributed to the ESAM in the battery module for the additional decryption operation in the data exchange.
4 Background Management System
Since the electric vehicle battery is running in operation, it may be circulated in multiple users, multi-region, and the background management system is mainly used for the storage and management of all information. The information can be read from the battery security module via a handheld or a fixed read head, and finally consolidation in the background management system, which is easy to uniform asset control and information management.
Install the encryption machine in the background system to deal with the additional data of upload data.
5 ESAM security realization mechanism
Different according to data security requirements, the battery module and the outside data exchange can be used in the following four modes: clear text, ciphertext, expressly text plus check or secret text plus check mode. The encryption of the data ensures the reliability of the data, and the data integrity and the sender are implemented by using the check code. The encryption mode is to transmit the message data to be transmitted. After the transfer is transferred; the verification mode is to encrypt the message data to be transmitted to encrypt a 4 B check code MAC, packaged to the data to be transmitted together. After receiving the data, the receiver is discriminated according to the MAC; and the encrypted verification mode is used for the length [5].
5.1 identity
Take the number of randhes in the battery module ESAM and encrypt the calculation to generate data, upload to the handheld terminal, and then perform internal ciphertext calculations in the handheld terminal, the core generates the internal cipher, to realize the terminal equipment pair If the battery module is legitimate, the process is shown in Figure 2.
The random number is generated by the true random number generator built in the ESAM, and the true random number generator generates a random number using the internal electromagnetic white noise, eliminating the possibility of the pseudo-random number due to periodicity, thereby ensuring the security of the encryption process Sex [6].
5.2 Data Interactive Process
When the identity is passed, the next step of data interactive flow can be entered, that is, the battery module communicates and data interact with the outside handheld or charging pile.
For data stored in the battery module, classified by the importance of data files, permission settings such as read / write and other operations, respectively. The higher the safety requirements, the higher the encryption level, the level of encryption mode, the level of encryption, the security requirements are low, the encryption level can also be reduced accordingly, that is, the corresponding encryption method can be reduced or transparent, it is not encrypted, it is used to improve Communication speed and redundancy calculation. Therefore, in accordance with different needs of safety level, it is used in plaintext, ciphertext, clear text + check, ciphertext + check 4 methods.
In the ESAM of the battery module, the key file encryption level, because the ESAM security chip used in the battery management system is hard-encrypted mode, all key files can not be changed, but freely, secure levels for transmission Data of the data.
The rest of the data, such as applying information files, divided into transparent files and opaque files according to the security level. Such as charging documents, asset information, etc., due to important information such as asset-owned and charging, the number of charges, etc., so on security requirements, this part of the file is an opaque file, when interacting communication, use ciphertext + check mode, To ensure that the third party cannot be decompiled and modified during the space transmission process; some battery run information files do not need to perform MAC check, communicate with ciphertext; such as battery address query, broadcast institution, etc., due to Does not involve user or owner privacy information, there is no need to use ESAM to communicate directly with the battery module to save communication time.
5.3 Safety Management System
Due to the addition of the security module, the electric vehicle battery is connected to the back-end primary station through the supporting key system during circulation, thereby achieving asset control of electric vehicle batteries.
When the electric vehicle battery is charged, the electric vehicle module communicates with the charging pile through BMS. Only after the identity is passed, the charging pile will charge the battery. At the same time, the charging pile can also read the relevant information within the battery module and transferred to the background system backup, and the operator can check the flow of the battery at any time through the background system.
The same read and write devices can also be configured on a fixed read head or handset for use in the entry library or manually querying battery asset information.
In addition to securely securely in the program algorithm process, in the application management system, the licensed passwords are set separately on the background system software and handlers, which are used for security management of information within the system.
6 Conclusion
As one of the development directions of future possible transportation, the development of electric vehicles is particularly attractive. Among them, electric car batteries are one of the important components and technologies in electric vehicles. Based on the ESAM security module, the handheld terminal, introduces the improvement of the electric vehicle battery management system, improve the safety of the battery, so that it is more systematic, safe, convenient, and has a deep development of further promotion and application of future electric vehicles. The impact.
Source: Wiku Electronic Market Network
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