See what's behind the electronic system that controls the lithium-ion batteries in EVs

Being a co-founder of Solidstudio, Paweł has got to see all the development phases. He’s a skilled professional with years of experience, both in the software and in the eMobility worlds.

Paweł Głogowski

, we’ve briefly touched upon some of the emerging technologies in the world of eMobility. One of them (admittedly, not-so-emerging as it's been going on for a while) was the 

 used in EVs. It’s now time to shed some more light on what it is.

Surely, the batteries may be regarded as the core of any electric vehicle. Essentially, it is what gets the car going. It’s also what determines to a great extent how appealing an EV can get for the potential buyers. Thus, ensuring the battery runs smoothly, safely and efficiently is paramount in the EV formation process. Here’s where BMS kicks in.


) is a system that monitors and manages a rechargeable battery (or group of batteries), such as those found in electric vehicles, UPS systems, and solar energy storage systems.

The BMS is responsible for protecting the battery from operating outside its safe limits, maximizing its lifespan, and providing accurate information about the battery's state of charge, state of health, and current capacity. 

In short, its primary functions can be narrowed down to ensuring the battery remains safe and reliable.

A BMS typically consists of a control unit, sensors, and connection wires. The control unit may be a separate device or integrated into the battery pack. The sensors monitor various parameters of the battery, such as voltage, current, temperature, and state of charge. The connection wires carry power and data between the battery and the BMS.

The control unit uses the information from the sensors to determine when to charge or discharge the battery, how much power to allow in or out, and whether the battery is operating within its safe limits. If the battery is operating outside its safe limits, the BMS will take action to protect the battery, such as disconnecting it from the load or shutting off power altogether.

The BMS may also provide information about the battery to a user or system, such as the current state of charge, state of health, and remaining capacity. This information can be used to optimize the performance of the system in which the battery is used.

A BMS typically includes safety features to protect the battery, such as overcharge and over discharge protection, short circuit protection, and thermal runaway protection. These safety features help to prevent damage to the battery and ensure that it operates safely.

The BMS may also include features to maximize the lifespan of the battery, such as balancing. Balancing equalizes the voltage of the cells in a battery pack, which helps to prevent capacity loss and extends the lifespan of the battery.

Battery management systems are used in a variety of applications, including electric vehicles, UPS systems, and solar energy storage systems. BMSs are an important part of these systems, as they help to protect the battery from damage, extend its lifespan, and provide accurate information about the battery's state.

With lithium-ion, an average battery module consists of packs of single battery cells. That is because a singular cell doesn’t hold enough capacity to power the bigger establishments. In such cases (where there are multiple modules connected to make up for a battery) monitoring and managing becomes rather complicated, as the singular cells can charge differently.

BMS collects data gathered from the batteries (in real-time) and based on the information it acts accordingly. Amongst the parameters collected  there are:

Once these are collected, the BMS system will process it. The outcomes of such processing is the below data:

State of charge (SOC)- an estimation of how much charge the battery currently has - while in use

State of health (SOH) - an estimation of the capacity/condition of the battery, it measures how well the battery is able to hold a charge

Issues - monitoring and addressing any recognized malfunctions

Based on the outputs, the BMS then takes action to protect the battery, such as turning off charging when the SOC is full or shutting down the system when a cell is over temperature.

There are two main types of BMSs. The first is a 

, which uses one control unit to manage all of the battery cells in the system. The second type of BMS is a 

, which uses multiple control units to manage the battery cells in the system.

The main advantage of using a centralized BMS is that it is simpler and cheaper to design and build. The main disadvantage of using a centralized BMS is that if the control unit fails, the entire system will fail.


The main advantage of using a distributed BMS is that it is more resilient and can continue to operate even if one or more of the control units fails. The main disadvantage of using a distributed BMS is that it is more complex and expensive to design and build.

Which type of BMS is best for a given application depends on the specific requirements of the application. For example, if cost is the primary concern, then a centralized BMS may be the best choice. If reliability is the primary concern, then a distributed BMS may be the best choice.

In terms of the use of BMS in automotive, it doesn’t differ from any other means. It helps to ensure that the battery pack lasts for as long as possible and performs at its best. A well-designed BMS can make the difference between a battery pack that lasts for years and one that needs to be replaced frequently. This can have a significant impact on the overall cost of ownership of an electric vehicle.

Amongst the vital aspects that get covered by BMS in EVs, there are:

Thermal management - much like any other batteries, the ones installed in EVs can overheat. With thermal management, the censor units control the temperature and, if it get too high, they trigger the cooling mechanisms

Discharge and charge control - the primary function of any BMS is to protect the cells within the battery pack from being over-discharged or overcharged. To do this, the BMS will cut off the discharge path when the cell voltage drops below a certain threshold, and will also cut off the charging path when the cell voltage reaches a higher threshold.

Battery balancing - In order to ensure that all the cells in the battery pack are at the same voltage, the BMS will occasionally "balance" them by equalizing the voltages of all the cells. This is usually done during charging, when the cell voltages are highest.

Communication and Safety monitoring - Some BMS systems also have a communication interface that allows them to be connected to a computer or other devices. This can be used for firmware updates, data logging, or even remote control of the BMS. Additionally, BMS systems have built-in safety features that can monitor the system for faults and take appropriate action if a problem is detected.

ISO 15118 - what is it?

Learn about the wireless EV charging and its possibilities and obstacles.

Grzegorz is the Head of Development in Solidstudio and he has spent quite a few years here. He’s a skilled software developer that had a chance to work on numerous eMobility-related projects for clients from many different countries.

Grzegorz Bar

It wasn't that long ago when electric cars were nothing short of a pipe dream and a daring vision of the future. It didn't take that much time for it to become the new reality, still in development, but definitely no longer a futuristic delusion. As much as there's yet a lot of work at the grass root to be carried out, especially in terms of the charging infrastructure, major technological advancements can be observed at any level of eMobility undertakings.


This is further true when we take a closer look at some of the latest trends in eMobility. We can see that many new technologies are being developed to make electric cars more efficient, more reliable and cheaper to maintain. Some of these trends include:

- allows for the quick and easy exchange of batteries in electric vehicles. This means that drivers will no longer have to wait for their batteries to charge, which will make electric cars more convenient to use.

 - allows drivers to charge their electric vehicles without having to plug them into a charging station. instead, they can simply place their car on a special pad that will wirelessly charge the battery.

 - allows electric vehicles to be charged by the sun. Solar panels can be used to collect solar energy and then convert it into electrical energy that can be used to charge an electric vehicle. This renewable source of energy will make it easier for people to use electric cars.

Electric Vehicle Battery Management Systems

 - helps to keep electric vehicle batteries healthy and working properly. These systems can monitor the battery's health, charge level, and temperature. They can also help to extend the life of the battery.

 - can charge an electric vehicle's battery in a matter of minutes. This will make it easier for people to use electric cars, as they will not have to wait long for their batteries to charge.

 - these cars are connected to the internet and can drive themselves

Big Data and Predictive Analytics for Electric Vehicles

 - can help to predict when an electric vehicle will need to be charged. It can also help to find the best route for an electric vehicle to take.

Blockchain Technology for Electric Vehicles

 - can help to secure data about electric vehicles. It can also help to provide a way for people to pay for electric car charging.

 - can help to create a network of electric vehicles that can provide power to a grid

In this entry, wireless charging is what we’re going to focus on. First, let’s see what wireless charging is in general. Wireless charging is a technology that allows devices to be charged without the need for a physical connection (i.e. through the cable). This means that instead of plugging your device into a power outlet, you can simply place it on a wireless charging pad.  What's interesting is that the first prototypes of such technology were created by Nikolai Tesla, back in the late 1800's, when he managed to transmit the electricity through air.

Wireless charging technology uses an electromagnetic field to transfer energy between a charging pad and a device. The charging pad is connected to a power outlet, and the device has a built-in receiver that converts the energy into electricity that can be used to charge the battery. This is accomplished by using a copper coil, which creates an oscillating magnetic field. The receiver then converts the current into DC power, which is used to charge the battery.

There are mainly two types of wireless charging: inductive and resonant. Inductive charging is the most common type, and it uses magnetic fields to transfer energy between the charger and the device. Resonant charging uses electromagnetic resonance to transfer energy, and it is less common.

Now, how does it work for EVs? There isn’t any difference to how this happens with electric cars. The car charging session starts when electricity is transferred from one magnetic coil in the charger to another by way of an induction process. The coils need both be aligned with each other, which means that the driver has to park directly over it to enable the charging event. The wireless chargers come in the shape of a flat pad, making it relatively easy to maneuver the car over them.


Wireless EV charging is still in its infancy but there are already a few companies working on the technology, including big automotive players like BMW or Volvo. The big obstacle in working with wireless charging is the lack of broad, widely-accepted standardization. Here’s where The Society of Automotive Engineers has come to help by developing a standard for wireless EV charging, which should help to speed up the adoption of the technology.

SAE J2954 is the aforementioned standard for wireless EV charging. In the official documentation about the standard we read:

“ The SAE J2954 standard establishes an industry-wide specification that defines acceptable criteria for interoperability, electromagnetic compatibility, EMF, minimum performance, safety, and testing for wireless power transfer (WPT) of light-duty plug-in electric vehicles. The specification defines various charging levels that are based on the levels defined for SAE J1772 conductive AC charge levels 1, 2, and 3, with some variations. A standard for WPT based on these charge levels enables selection of a charging rate based on vehicle requirements, thus allowing for better vehicle packaging and ease of customer use. The specification supports home (private) charging and public wireless charging.”

The charge levels mentioned above are (at least for now): 3.7kWh, 7kWh and 11kWh, leaving the room for improvements in this area for sure. The standard’s development took almost a decade, meaning that the upcoming changes may take a bit of time to be included.

Wireless EV charging - the benefits and the obstacles

For as long as wireless charging remains in its infancy, it's a bit hard to speak about the advantages, as currently there aren't many in practical use. Although, it doesn't mean that the technology itself won't have much to offer in case it gets developed to the point of mass adoption.

Wireless charging for electric vehicles would be a convenient and efficient way to keep your car charged without the hassle of dealing with cords and plugs or finding a parking spot near a charging station. Wireless charging would make a perfect case scenario for electric taxis or buses, which all have their frequent stops. Such an undertaking is already taking place in Gothenburg, Sweden. The pilot project involves a fleet of taxis (consisting of the electric Volvo XC40s) and a suite of charging pads developed by an US company - Momentum Dynamics. The chargers are installed in specially prepared parking spaces. Such a venture allows not only for the electric taxi fleet to remain charged but also makes up for a great test-environment to gather the data, learn about some issues and implement solutions.

However, before we ever get to witness and enjoy the giftings of wireless charging, there are some quite substantial obstacles to overcome.One of the biggest obstacles to widespread adoption of wireless EV charging is the lack of infrastructure. Wireless chargers need to be installed in convenient locations where EV owners can easily access them, and right now there are very few public places that offer wireless charging. This means that most people who want to use wireless charging will have to install a charger at their home or workplace, which can be expensive and time-consuming.

Wireless charging technology is still in its early stages of development, and there are a number of technical challenges that need to be overcome before it can be widely used. For example, current wireless chargers can only transfer a limited amount of power, which means that they can take a long time to charge an EV. These technical challenges are being addressed by research and development, but it will take some time before they are resolved.

Wireless charging technology is currently more expensive than traditional wired charging, both in terms of the initial cost of the equipment and the cost of installation. This is one of the main reasons why wireless charging has not been more widely adopted so far. However, as the technology develops and becomes more widespread, the costs are likely to come down.

There are some safety concerns associated with wireless EV charging, as the chargers emit electromagnetic fields (EMFs). Although there is no evidence that EMFs are harmful to humans, some people are still worried about the potential health effects. These concerns need to be addressed before wireless charging can be fully accepted by the public.

Wireless EV charging is a promising technology that has the potential to make EV ownership more convenient and reduce the environmental impact of transportation. However, there are a number of obstacles that need to be overcome before it can be widely adopted. These include the lack of infrastructure, technical challenges, cost, safety concerns, and the lack of standardization. With continued research and development, these obstacles can be overcome and wireless charging can become a mainstream technology.

Wireless EV charging

Get our informative PDF on ISO 15118 and learn more about the standard.

Being an eMobility leader in various projects across multiple startups, Piotr was responsible for OCPI and OCPP integration as well as EMP and CPO platforms development. With extensive expertise in the open standards field and eMobility tech solutions, he is leading teams of experienced developers and contributing with invaluable knowledge and experience.

Piotr Majcher

Interoperability and standardization have become a big part of the EV transformation. As the industry evolves, more and more players come to the game, bringing new developments and ideas. With that, the entire ecosystem undergoes massive changes and it may get difficult to keep track of what’s happening.

That way, interoperability is critical for eMobility. 

Open standards are necessary to ensure that different types of electric vehicles can interoperate with each other and with the infrastructure that supports them, which is run by multiple CPOs and EMPs.

ISO 15118 is an international standard that defines the communication protocols and data structures used in electric vehicle charging. It specifies the two-way communication between Electric Vehicles (EV), including Battery Electric Vehicles and Plug-In Hybrid Electric Vehicles, and the Electric Vehicle Supply Equipment (EVSE).

Communication protocols and data structures

ISO 15118 is designed to be interoperable, meaning that EVs and EVSEs from different manufacturers should be able to communicate with each other. The standard is also designed to be scalable, so that it can be used for both residential and public charging stations.

It enables interoperability between electric vehicles and charging stations, and allows for sophisticated features such as billing based on time of use or energy consumption. ISO 15118 also provides a framework for charging station operators to manage access control and load balancing.

ISO 15118 is built upon Public Key Infrastructure (PKI)

, which means  electric vehicles can be identified and authenticated. This authentication can take place before, during or after a transaction.

The standard is built out of 8 parts, each defining a different aspect covered by ISO 15118 as a whole.

To learn more about ISO 15118, its specifications and features as well as how it works and what are the documents defining each functionality, download the paper from the box on the right side of the page.

Learn about the plug and charge technology and see how it simplifies the charging experience.

In the last few years, there have been plenty of ameliorations introduced to ease the EV charging experience. Whether it’s hardware or software, major changes for the better can be observed even in places where eMobility does not have its wings spread with a full potential. Yet, even the major progress in EV charging technology, doesn’t stop frequent comparisons to what it looks like with maintaining an ICE car, which tends to be described as less complicated and simply easier.

Luckily, this view is being gradually changed by technologies implemented into the world of EV charging. In this article, we’ll take a closer look at one of the most promising charging-simplifying facilities.

allows for an EV charging event without the necessity of additional means, such as RFID cards or apps.

 With Plug and Charge, the data exchange between a charger and an electric vehicle occurs entirely automatically. This includes the authentication and authorization processes. It makes the charging process much more convenient for drivers. They don’t have to worry about connecting their vehicle to the charger or starting the charging process manually. In addition, Plug and Charge also offers improved security, as the data exchange between charger and vehicle is encrypted. It makes an EV charging experience more similar to fueling an ICE car, which does not require a sequence of minor actions to authorize a charging session.

The technology behind Plug and Charge is based on the 

. This standard defines the communication protocols and data formats that are necessary for an automated, interoperable charging process (more about it in the next section).

In order to use Plug and Charge, an electric vehicle must be equipped with a so-called Charging Control Unit (CCU). The CCU is the interface between the vehicle and the charging station. It manages the data exchange with the charger and controls the charging process. What must be remembered is that plug and charge facilitates the communication between all parties involved in the charging process, that is:

In simple words, with Plug and Charge compatible devices, the EV contains provisioning certificate and contract certificate (between the driver and EMP) and charging station contains EVSE certificate.User is identified by the ID called E-Mobility Account Identifier (eMAID) stored in the contract certificate. eMAID is also known to the eMSP for billing purposes. Thanks to that, eMSP knows which user has to be charged for the transaction started automatically just by plugging the cable. The moment an EV cable is plugged into the socket, the charging station identifies the car's certificates and vice versa.

When plugging in at a Plug and Charge enabled charger, the CCU will automatically initiate the data exchange with the charger. This includes exchanging information about the maximum current that can be drawn, the maximum voltage that can be applied, and the plug type.

Based on this information, the charger will adapt its settings accordingly. Once the connection is established, the charger will start supplying electrical energy to the vehicle. The entire process happens automatically and doesn’t require any interaction from the driver.

ISO 15118 is a joint venture of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) and one of a group of standards for electric vehicles. It describes the communication between a vehicle and a charging point. It has few use cases and Plug and charge is one of them.



Whole ISO 15118 is built upon Public Key Infrastructure. In Plug and Charge - The EV has the contract certificate stored (X.509 certificate). The certificate associates the end-user with the public key. Because the certificate is issued by a trusted Certificate Authority, the charging station is able to check it, and if it’s valid, the charging station believes that the user presented in the certificate is not fake. The standard ensures high security of the data exchange amongst all involved parties. The security is provided via authenticity (the verification of certificates) and confidentiality (data exchange happening via encrypted channels).

As it rapidly gains popularity amongst eMobility-related operators, ISO 15118 can be deemed one of the crucial means in ensuring the seamless operation in the world of EV charging.

In terms of its other use cases, we dive deeper into the smart charging and V2G functionalities and importance in our recent downloadable guide 

OPCP is an open standard launched by Hubject. The launch of OPCP simplifies the process of adopting the Plug and Charge technology for developers and eMobility stakeholders looking to deliver the best solutions for EV users. Standardization of said technology is a great step towards increased interoperability and unification across the industry.

Being an open protocol, OPCP gives everyone interested the opportunity to utilize Plug and Charge technology. As stated by Hubject:

“This measure is particularly relevant because the rapidly growing market for Plug&Charge results in a range of very different processes from different manufacturers. After all, unhindered access without lock-in effects will be an essential criterion for Charging Station Operators and Mobility Service Providers, offering charging solutions. In addition, qualities such as the simple and secure authentication methods for different applications and the option for further joint development in cross-sector mode are convincing. Furthermore, the opportunity for multi-contract handling is given. Multiroot handling is also implemented and compliant with ISO15118-20.”

The protocol is constantly being developed and Hubject invites any feedback and improvement ideas.

OPCP is in productive use since 2019 and is gaining more and more users amongst Charge Point Operators, eMobility Service Providers and OEMs.

It’s to no surprise, as the launch of OPCP opens the door for many to enjoy the benefits of the technology., making the charging experience a lot more effortless for the end-customers - EV drivers.


The protocol covers the following use-cases:

 (Root Certificate Pool: used for communication between the Root Certificate Pool and the various Certificate Authorities of ISO 15118 participants (V2G, OEM, MO, CPS)

 (The Provisioning Certificate Pool: providing interfaces to exchange Provisioning Certificates between OEMs and MOs)

(Certificate Provisioning Service: providing interfaces for generating and signing contract data of MOs)

CCP Service (Contract Certificate Pool: stores the signed contract data from the MOs, and provides it for the CPOs and OEMs backend)

Multiple Contracts (EMAIDs) for one Vehicle (PCID)

Interoperability between Ecosystems, V2G Root Operators etc

Multi Root -> CertificateSigningCertificate ability

ISO15118-20 prepared (separate Namespace already in account)

Battery Management System (BMS)

25 AUGUST 2022 • 7 MIN READ