The first battery pack sensor monitoring chip protects the safety of power batteries

At present, intelligence has become a key track in the field of new energy vehicles . Intelligence is inseparable from sensors. Sensor chips are closely related to the perception and processing of vehicle voltage, current, temperature and other working condition information. In the process of the transformation of automotive electrical architecture from distributed to centralized, Pingjie Electronics has seen the huge market space and has become one of the few domestic sensor chip suppliers involved in automotive functional safety.

The biggest technical difficulty in the industrialization of power batteries is the safety of battery pack thermal runaway. Relying on its profound technological accumulation, Pingjie Electronics launched the first domestic battery pack sensor monitoring chip to ensure the safety of power battery packs.

Power battery packs pose a risk of self-ignition

After several years of development, the electrification of the automotive industry has now come to an end, and intelligence has become a track that OEMs and Tier 1 are really paying attention to. Intelligence is closely related to sensors. In fields such as new energy vehicles, energy storage, and industry, the market size of sensors is expected to exceed 250 billion yuan in 2025. Accelerating domestic substitution and product innovation is a big test that domestic automotive sensor manufacturers need to face.

In the process of developing automotive sensing chips, industry-leading Pinjie Electronics also paid attention to the functional safety issues of the power battery pack, the "heart" of new energy vehicles.

Batteries inevitably undergo thermal runaway. Batteries with higher energy density have lower thermal stability. In recent years, spontaneous combustion incidents of electric vehicles have occurred frequently, and the thermal safety of lithium batteries has become a top priority for electric vehicles and energy storage systems. So why do power batteries frequently catch fire? How to deal with it?

Power battery pack structure and thermal runaway principle

The materials required for the production of power lithium batteries include positive electrode materials, negative electrode materials, electrolytes, separators and packaging materials.

Image source: Pingjie Electronics

Due to the characteristics of the lithium-ion battery structure, the SEI film, electrolyte, EC, etc. will undergo decomposition reactions at high temperatures. The decomposition products of the electrolyte will also react with the positive and negative electrodes. Various reactions will cause the generation of a large amount of heat. The melting of the diaphragm causes an internal short circuit, and the release of electrical energy increases heat production. This accumulated destructive effect often causes the explosion-proof membrane of the battery core to rupture, the electrolyte to eject, and a fire to occur.

Image source: Pingjie Electronics

The abuse of lithium-ion batteries is divided into mechanical abuse, electrical abuse and thermal abuse. All three forms of abuse may lead to internal short circuits and ultimately thermal runaway due to the interaction between electrode active materials. At this time, other flammable gas products and electrolyte vapor and oxygen generated by the anode are mixed with air at high temperatures. When the battery is out of control, a "burning triangle" is formed, that is, it burns or explodes.

How to achieve the "golden five minutes" of escape?

In 2020, the GB 38031-2020 standard "Safety Requirements for Power Storage Batteries for Electric Vehicles" issued by the Ministry of Industry and Information Technology clearly stipulates that if a battery pack experiences thermal runaway, an alarm must be issued five minutes in advance to allow escape time for drivers and passengers. Based on this functional safety requirement, battery manufacturers have also added many new battery thermal runaway prevention and management measures in addition to the traditional BMS system.

There are two major measures to prevent thermal runaway: active protection and passive protection.

Active protection design is divided into electrical abuse prevention, mechanical abuse protection, thermal abuse protection and thermal runaway warning. Once thermal runaway occurs, an alarm can be provided in time so that drivers and passengers can evacuate as soon as possible; passive protection involves the optimization and strengthening of battery cells and system structures. and thermal barrier design.

It can be seen that in the face of the functional safety challenges of power batteries, only efficient and reliable battery management solutions can ensure battery safety during vehicle use.

Battery pack sensing monitoring chip enables thermal management

As mentioned above, thermal runaway can easily cause battery packs to catch fire or even explode. In this regard, in addition to active protection measures such as BMS and reinforced shell protection, Pingjie Electronics has launched BPS and BAS battery pack sensing monitoring products to provide safety guarantees for the battery systems of new energy vehicles at the chip level.

Image source: Pingjie Electronics

According to the official website of Pingjie Electronics, BPS-SNP805, as the first domestic battery pack pressure sensing monitoring chip, is specially designed for new energy vehicle battery pack pressure monitoring applications. The chip has a built-in 8-bit MCU, 12-bit high-precision ADC, temperature sensor, air pressure sensor and power supply voltage monitoring unit. The chip can measure the pressure changes of the battery pack in real time and provide an alarm signal when the pressure changes exceed the normal range.

BPS-SNP805 battery pack pressure monitoring sensor chip Image source: Pingjie Electronics official website

At present, ternary batteries mainly adopt pressure monitoring solutions. The BPS module is based on micro-mechanical pressure (MEMS Pressure) and application-specific integrated circuit (ASIC) technology to achieve accurate detection of environmental pressure.

During the thermal runaway process of ternary lithium batteries, the cathode material will release oxygen, and the oxygen will react with the solvent to produce a large amount of gas and heat. The pressure and temperature of the battery pack rise rapidly in a short period of time. Thermal runaway can be monitored through high-precision pressure and temperature modules and alarmed in advance.

Lithium iron phosphate batteries mostly use BAS sensing monitoring solutions. For lithium iron phosphate batteries, Pingjie Electronics' BAS module is based on optical smoke detection and application-specific integrated circuit (ASIC) technology, which can achieve accurate detection of environmental aerosol concentration.

In terms of BPS and BAS chips, Pingjie Electronics is currently the only chip supplier in China. Its BPS and BAS chips integrate temperature, pressure sensors and power supply voltage detection units. It not only has the integration advantages of small size and low cost, but also has low power consumption, supports multi-zone alarms and supports multiple alarm modes. When the battery undergoes thermal runaway, the user will be given at least five minutes of golden escape time.

Focus on automobiles and industrial Internet of Things to create domestic “core” momentum

Pingjie Electronics focuses on automotive and industrial IoT applications and is committed to providing excellent automotive electronic sensing chips and complete system solutions.

Automotive sensing is an extremely segmented track in the automotive industry. Choosing to use sensing as the entry point to engage in chip design will undoubtedly lack a lot of experience to learn from. Dr. Li Mengxiong, chairman and general manager of Pingjie Electronics, returned to China in 2015 to found Pingjie Electronics. He said frankly, "Wireless sensing is a particularly clear direction. Choosing this direction to start a business is actually a relatively bold decision."

As one of the few domestic sensor chip R&D and design companies involved in automotive functional safety level, Pingjie Electronics' TPMS (tire pressure monitoring) chip has broken the monopoly of foreign chip suppliers since its mass production in 2017. With its stable and reliable performance, Gain industry recognition. It is reported that Pingjie Electronics has reached in-depth cooperation with many well-known sensor manufacturers at home and abroad. Now, the company has six major product lines and shipments have reached tens of millions. From signal sensing to signal processing to in-vehicle wireless transmission, it already has a full-stack IP and patent layout.

Image source: Pingjie Electronics official website

In the future, Pingjie Electronics will also launch a series of smart sensor chips for signal sensing, processing and transmission, especially wireless transmission, to fully meet the needs of the automotive market and industrial fields under the trend of integration, wirelessness and localization.