AMR Battery Technology for High Current Pulse AMR Meter Systems
Autonomous Mobile Robots (AMR) are becoming increasingly important to the world of production and logistics. These systems can be a game changer when it comes to sorting packages, picking items and transporting materials.
However, they come with some roadblocks that need to be overcome. The key is to ensure that these robotic vehicles are running efficiently.
Long-lasting Li-ion batteries
Long-lasting lithium batteries are available to power the many features and functions that make up today’s AMR meter systems, including those that require high current pulses. Tadiran has developed a pair of battery technologies that address these challenges: PulsePlus (Figure 4) and TRR Series.
AMR meter design technology is evolving rapidly, and new systems are becoming increasingly feature-rich and energy-hungry. This has pushed traditional lithium thionyl chloride (LiSOCl2) chemistries to their limits in some applications.
These newer devices often generate a high current surge at periodic intervals, which can severely affect battery performance. This is particularly true when the device requires low self-discharge and a long life.
To avoid these problems, battery manufacturers need to use quality raw materials and manufacturing techniques that are consistent throughout the product line. This will help prevent batch-to-batch inconsistencies, which can significantly impact battery performance over time.
Another important consideration for battery manufacturers is the chemistry of the electrolyte, which can also impact AMR Battery the voltage and self-discharge rate of the battery. As a result, it’s crucial to select an electrolyte with the correct balance of ionic conductivity and chemical stability, and which can withstand the specific demands of a given application.
Alternatively, manufacturers can use a proprietary lithium thionyl chloride formulation that is designed specifically to maximize long-term battery performance in AMR metering systems. This type of chemistry offers the ideal combination of energy density and capacity for these applications, while providing the lowest self-discharge rates of all available lithium chemistries.
In addition to ensuring that the lithium thionyl chloride cell is matched with a suitable electrolyte, battery manufacturers must take into account other factors such as temperature and impedance. Impedance, which reflects the internal resistance of the electrolyte, can increase when the battery is subjected to certain high current surges, resulting in a reduction in load voltage.
In order to minimize the effect of battery impedance, battery manufacturers can blend special additives into the electrolyte. This will improve the ionic conductivity and thereby reduce the impact of impedance on battery performance. It will also ensure that the electrolyte is at the right pH level for optimum lithium battery performance, which is especially essential when the battery is operating in extreme temperatures.
Intelligent battery management systems
A battery management system (BMS) is the core component of a smart lithium battery pack. It regulates the flow of power based on temperature, cell voltage and currents in order to maximize battery life, performance and durability.
Especially in high-voltage applications, BMSs are essential to ensure that all battery cells within the pack remain safely operational. Mismanagement could lead to dangerous outcomes that range from compromising battery performance to outright destruction.
In addition, smart battery systems monitor the state of charge, health and safety of each individual cell within a pack. This gives operators the ability to make informed decisions about battery replacement and battery maintenance to maximize operational efficiency.
To address these challenges, AMR Battery offers a line of intelligent lithium iron phosphate batteries (LiFePO4 batteries). LiFePO4 batteries offer the best of both worlds – maximum energy density and minimal risk, avoiding problems with overheating, combustion, or hazardous materials.
Another key advantage of these smart batteries is their compatibility with intelligent telematics and other systems that allow AMR/AGV to transfer real-time data about the battery, how much power it is drawing, and how long it will be before it is completely discharged. This information can help the AMR/AGV avoid cutting off in the middle of a job and spend that downtime on charging.
The distance driven by an AMR is also a critical factor for proper battery management. AMRs that are running in large facilities with long paths between pickup and drop off will rundown their battery faster than those with shorter runs.
This is where intelligent battery systems come in handy, as they can detect this AMR Battery pattern and take steps to prevent the AMR/AGV from cutting off in the middle of a job. This enables the AMR to spend that downtime on opportunity charging, thereby increasing uptime.
A battery management system should also protect the cell from passivation, which is a build-up of an electrochemical layer that can reduce the capacity of a lithium cell. To minimize this issue, BMSs should work closely with the AMR/AGV system’s designer to implement special protocols that call for more regular high current pulses that don’t leave the cell inactive for extended periods of time.
Reduced downtime
As AMRs and AGVs become a key component of warehouses and distribution centers, it is critical that their batteries are able to operate continuously at full capacity. This is especially true as they function without a human operator. Fortunately, lithium-ion batteries are a great choice for supporting AMRs and AGVs in warehouses because they offer fast charging, lower maintenance, higher energy density, and longer-lasting charges.
Unlike lead-acid batteries, which require watering and can deteriorate quickly when exposed to harsh conditions, lithium-ion batteries do not need any kind of maintenance. They also last longer than lead-acid batteries and do not have a reduced service life after deep cycling.
In addition, Lithium-ion batteries are designed to withstand long periods of high pulses. This is an important advantage since it ensures that AMRs can be used safely and effectively throughout the day in extreme temperature conditions.
To make the best use of this feature, it is important to select a battery chemistry that offers good operating characteristics under these conditions. This means choosing a cell that combines high voltage (typically 2.9 V), excellent temperature characteristics and low self-discharge.
For these purposes, Tadiran recommends using bobbin-type lithium thionyl chloride (Li-SOCl2) batteries as they offer the highest performance in AMR applications. This chemistry has a few key advantages over other options, including a rust-resistant coating that prevents the metal lithium in the cells from reacting with the liquid electrolyte, which results in a ‘passivation’ layer that protects the cells during storage.
Furthermore, Li-SOCl2 batteries are designed to withstand frequent high current pulses and remain in operation for a long time, which is essential for AMR systems. In addition, the chemistry is able to handle the high temperature, humidity and dust environments associated with these operations.
Another way to maximize the performance of your AMRs and AGVs is to utilize contact-free chargers that allow for quick in-process charging. This allows AMRs and AGVs to charge their batteries while performing processes such as loading/unloading and turnarounds. This can help AMRs and AGVs to operate more efficiently, increasing throughput and reducing maintenance costs.
Flexibility
In a manufacturing or warehouse setting, AMRs and AGVs can offer businesses flexibility for a variety of purposes. With interchangeable top modules like conveyors and robot arms, these systems can move about a facility, taking up space only when and where they’re needed. This allows companies to maximize the efficiency of their workflow, reduce their energy costs and stay flexible for future changes in their needs.
Another reason that AMRs and AGVs are ideal for material handling is the fact that they can take up less space than traditional fixtures. Since these batteries are lightweight and small, they can fit into any available space without a significant impact on floor space.
Additionally, AMRs and AGVs can be charged while in use, avoiding the need to interrupt production for battery replacement. This eliminates downtime, which can have a negative impact on productivity.
Moreover, lithium batteries are more durable than lead-acid batteries and can withstand heavy workloads for much longer. They also require fewer replacements, which helps keep the costs of AMRs and AGVs down.
This means that businesses can use AMRs and AGVs in a wider range of applications than ever before, making them an ideal option for many different types of warehouse and logistics facilities. Because of this, AMRs and AGVs are becoming a standard fixture in the materials handling industry, helping to ensure that a company’s warehouse is able to function at maximum efficiency.
For this reason, it’s important for manufacturers to choose the right type of battery for their application. For example, a high-pulse application such as automated meter reading (AMR) requires a more powerful battery than is necessary for standard wireless communication applications.
Because of this, it’s important to ensure that the battery chemistry chosen is capable of supporting the high pulse requirements. Currently, a primary lithium cell is the best choice, as it offers the most reliable performance and longest operating life.
However, a drawback to this chemistry is that it can build up a layer of ‘passivation’ over time, which could impair its ability to power the high-pulse AMR signals. For this reason, it’s essential to work with the battery supplier to design a system that calls for more regular high-current pulses, thereby reducing passivation effects.
