from chemistry to pack
Intelligent Battery Management Systems Battery Management Systems (BMS) are crucial for optimizing the operation of batteries by monitoring and controlling key parameters. Through real-time measurements of voltage, current, and temperature, BMSs can predict a battery’s performance, aiding in making informed decisions to enhance its lifespan and charging efficiency. The core functionalities include: These capabilities of … Read more
In any battery pack design it is only as strong as the weakest link [4], one bad cell or group of cells in the series string will control the total power and energy available from the pack. This means it is important to match the cells and to keep them balanced throughout the lifetime use … Read more
Contactors are the only moving part in a battery pack and although simple there are a number of contactor faults that will stop the operation of the battery pack. Introduction to Contactors There are two main types of contactors: Normally Open (NO) and Normally Closed (NC). A NO contactor does not allow current to flow … Read more
As a vehicle level systems engineer who spent many years working with an HV battery team, I naturally have some thoughts about opening and closing contactors. Here is my starter for 10 on the topic of ‘Control contactors’ 😇 Contactor Control is another one of those areas where responsibility is divided between a vehicle’s system … Read more
Cell temperature sensing is a critical function of any Battery Management System (BMS) this is because the cell temperature needs to be kept within a band to maintain safe operation. This band is narrower still to maintain the lifetime of the cell and hence reduce ageing. Cell Temperature For each cell the manufacturer will define … Read more
The centralized BMS has embedded all general functions (cell Voltage/Temperature/Series Current sensing, cell balancing… ) in a single control module/board, and was widely applied on smaller battery packs for commercial vehicles. The advantage of centralized architecture is reduced electronic component costs without slave PCBs required. Another advantage is accuracy, as centralized BMS use the same … Read more
Decentralized BMS Architecture is split into one main controller and multiple slave PCB boards. Consist of several equal units, which provide the entire functionality locally and autonomously. Each of the individual BMS units is able to operate independently of the remaining ones. Communication lines between the units enable information exchange and task coordination between the … Read more
There can be a number of reasons to do an Emergency Shutdown of a battery pack and a number of approaches to this. Hence interesting to layout and discuss this topic. It should be noted that we are discussing the BMS opening the contactors. The main reasons for an emergency shutdown are: Each of these … Read more
There are a number of reasons to estimate the charge and discharge current limits of a battery pack in real time: Hence this is a key function of the Battery Management System (BMS). The difficulty is that the current limits are dependent on a number of factors, for the cell alone we should consider the … Read more
If you are in a battery design role there is always pressure on increasing usable SoC window. Nobody wants to pay for and carry around unused battery capacity. However, there are some really good reasons to restrict that window. High SoC and hence high cell voltage stresses the cell and significantly reduces the lifetime. Going … Read more