EV Battery Repair: Cell vs. Module Replacement

Anatomy of an EV Battery Pack

The EV battery pack, the heart of any electric vehicle, is a highly sophisticated system composed of thousands of components working in concert. At its most fundamental level is the battery cell, the smallest unit that stores energy chemically. A single cell typically provides around 3 to 4 volts, which is far too low to power a vehicle. To achieve the high voltages and energy capacity required, hundreds or even thousands of these cells are arranged in a hierarchical structure.

Historically, this structure followed a Cell-to-Module (CTM) design. Individual cells were grouped into subunits called modules, which acted as self-contained, serviceable units with their own wiring and connections. These modules were then assembled into a larger, protective

pack, which also housed the Battery Management System (BMS) and the thermal control system. The CTM approach, as seen in older models like the first-generation Nissan Leaf and Chevy Bolt, made it easier for manufacturers to scale capacity and, crucially, to service the pack by swapping out a faulty module.

However, the industry is now in the midst of a significant shift driven by the relentless pursuit of greater energy density, lower costs, and faster manufacturing. Newer designs, such as

Cell-to-Pack (CTP), eliminate the intermediate module stage altogether. In this approach, cells are bonded or glued directly into the pack housing, resulting in a higher percentage of active battery material within the same volume. The most advanced iteration of this is the

Cell-to-Body (CTB) or structural pack, which integrates the battery cells directly into the vehicle’s chassis, making the battery a load-bearing component of the car’s skeleton. This engineering choice, while simplifying factory assembly and improving structural rigidity, has a profound impact on the long-term serviceability and repairability of the pack. The very design that makes the car more efficient to build and drive also makes it nearly impossible to service at a granular level.

Common Cell Types and Chemistries

The performance and safety of an EV battery are fundamentally determined by its cell type and chemistry.

Three main form factors dominate the market :

Cylindrical Cells: These are the most common and are often referred to by their dimensions, such as the 18650, 21700, and the larger 4680 used by Tesla. Their standardized, metal-cased design provides robust mechanical support and allows for natural cooling channels between cells. However, the space between the round cells can reduce volumetric energy density at the pack level.
Prismatic Cells: These are flat, rectangular metal boxes with excellent packing efficiency, meaning they waste less space inside the pack. They are often larger and heavier at the cell level but offer competitive system-level energy density. Prismatic cells are used in many modern EVs, including the BYD Blade battery.
Pouch Cells: Encased in a flexible laminate, pouch cells offer the highest energy density at the cell level due to the lack of a rigid casing. They are also highly adaptable in shape, allowing them to fit into unconventional spaces. The main trade-off is their mechanical fragility, which necessitates a more robust (and heavier) module structure to protect them.

Beyond form factor, the cell chemistry is a critical differentiator:

NMC (Nickel Manganese Cobalt Oxide) & NCA (Nickel Cobalt Aluminum Oxide): These are the most common chemistries for high-performance, long-range EVs. They offer high energy density, allowing for a greater driving range for the same pack size. However, their reliance on expensive and environmentally contentious materials like cobalt makes them pricier. They also have a shorter cycle life and a higher inherent risk of thermal runaway compared to other chemistries.
LFP (Lithium Iron Phosphate): This emerging chemistry is gaining popularity for entry-level EVs. It is significantly cheaper, safer, and has a remarkably longer cycle life, often exceeding 3,000 charge-discharge cycles. The primary drawback is its lower energy density, which means an LFP pack will provide less range than an NMC pack of the same weight or volume.

The Core Question: Cell vs. Module vs. Pack Replacement

The feasibility of replacing individual cells is not a simple yes-or-no question. It is a nuanced issue with significant technical, electrical, and safety barriers that often make it impractical.

Technical Challenges to Individual Cell Replacement

Mechanical Integration

The physical construction of a modern EV battery pack is the first and most imposing barrier to individual cell replacement. Manufacturers use a variety of techniques to secure cells and modules, and these methods are almost universally designed for manufacturing efficiency and durability, not for easy disassembly in the field.

Adhesives & Potting: Many packs are filled with industrial-grade adhesives and potting compounds that secure cells, improve thermal transfer, and provide structural rigidity. As demonstrated in a teardown of the BYD Blade battery, these glues are “stubborn and unforgiving” and require “destructive disassembly,” including cutting into the steel enclosure with a metal saw, a process fraught with risk. This extensive use of adhesives suggests a design that prioritizes durability over serviceability, creating a built-in barrier to aftermarket repair.
Welded Tabs: Instead of using bolted connections, many manufacturers utilize laser-welded busbars to connect cells and modules. This creates a robust, low-resistance electrical connection that is ideal for high-current applications. However, this type of connection makes it virtually impossible to remove a single cell without specialized equipment that is rarely found outside of a factory setting.

Electrical & Performance Matching

Even if a technician could physically access a single cell, the electrical challenges of replacing it are immense. A battery pack is a series-parallel network where every cell must perform in harmony.

The “Weak Cell” Problem: The primary issue lies in the electrical mismatch between a brand-new cell and the aged cells in the rest of the pack. A new cell has a higher capacity and lower internal resistance (IR) than its degraded neighbors. When this new cell is installed, it will charge and discharge at a different rate than the others. During charging, the new cell will fill up faster and remain in an over-charge state longer. During discharging, the older cells will be depleted more quickly, while the new cell still has a substantial charge. This imbalance can lead to a domino effect of degradation, potentially causing the entire pack to fail prematurely.
The Counter-Intuitive Reality: The goal of a cell-level repair is not to install a “perfect” new component but to find one that is “perfectly imperfect”—that is, matched to the aged state of the rest of the pack. This requires specialized equipment and expertise to “bin” new cells based on their precise capacity and internal resistance, a practice that is well beyond the scope of a typical repair shop.

Battery Management System (BMS) Complications

The BMS acts as the brain of the battery pack, constantly monitoring and regulating key parameters. A cell-level repair, whether successful or not, can cause a BMS to trigger a variety of fault codes and functional issues.

Limited Balancing Capabilities: While a BMS is designed to balance the state of charge (SOC) across cells, its ability to compensate for a severe imbalance in capacity or internal resistance is limited.
Recalibration: After a cell or module is replaced, the BMS must be recalibrated and resynchronized to clear fault codes and “re-learn” the new pack’s characteristics. This process is often proprietary and requires OEM-specific software, which is a significant barrier to independent repair. Without proper recalibration, the BMS may misreport the vehicle’s range or capacity, or trigger a safety shutdown.

Thermal Management Risks

Disrupting the pack’s finely tuned thermal system is one of the most dangerous aspects of an EV battery repair.

Hotspots: A new cell with a lower internal resistance will generate less heat than an older cell with higher resistance. This can create a temperature differential, or hotspot, that the pack’s cooling system is not designed to manage.
Thermal Runaway: If the cooling system is compromised, or if a cell is electrically mismatched, it can overheat and trigger a dangerous chain reaction called thermal runaway, which can lead to fire or explosion. Modern packs incorporate design features like bottom venting and physical barriers to prevent the propagation of thermal runaway, but these can be disrupted by an improper repair. This risk is a primary reason why working on EV batteries is a high-stakes procedure that requires meticulous attention to detail and professional training.

Diagnostics and Repair Workflow

The process of diagnosing a battery fault is a complex, multi-step workflow that requires a combination of sophisticated tools and expert analysis. A simple voltage check is insufficient to identify the root cause of a problem.

Identifying the Fault

The first step is to recognize the symptoms of a failing cell or module. These can include a significant decrease in overall capacity, a rapid discharge rate, inconsistent performance, and a noticeable temperature increase during charging or use. A visual inspection is also critical to check for physical signs of damage, such as swelling or bulging of the cells, which are a clear indicator of a major problem.

For a professional diagnosis, a technician’s toolkit must extend beyond basic hand tools to include specialized equipment:

Scan Tool: This is the primary diagnostic tool used to read diagnostic trouble codes (DTCs) and live data from the BMS. DTCs can provide a starting point for troubleshooting, pointing to a specific module or system malfunction.
Thermal Camera: A thermal imaging camera provides a non-invasive way to identify hotspots or uneven temperature distribution within the battery pack, which can quickly pinpoint a failing cell or a poor electrical connection.
Megohmmeter (Megger): A specialized tool for performing insulation resistance tests. It verifies the integrity of the high-voltage system’s insulation, a critical safety check both before and after a repair.
DC Internal Resistance (DCIR) Tester: This tool measures the resistance of individual cells under a controlled load, which is a key indicator of cell health and a crucial parameter for matching replacement cells to the rest of the pack.

The Decision Tree for Repair

The information gathered during the diagnostic phase is synthesized into a logical workflow that dictates the appropriate course of action. This decision tree is not a simple flowchart but a series of interconnected considerations:

Initial Triage: Begin with a symptom analysis and a scan for DTCs. If the BMS has logged a fault for a specific module, the technician can proceed to a more detailed inspection of that module.
Advanced Diagnostics: If symptoms are general, a thermal camera can be used to scan the pack and identify any abnormal temperature readings. This can be followed by a DCIR test on individual cells within the identified problem area to quantify their degradation.
The Repair/Replace Verdict: The final decision is based on a cost-benefit analysis of the data collected. If the vehicle has a modular battery design and only one or two modules are failing, a module replacement may be a cost-effective solution. However, if the pack has an integrated, structural design, a full pack replacement is often the only safe and viable option. The labor costs of a destructive repair, coupled with the risks of electrical imbalance and thermal runaway, typically make cell-level repairs economically and practically irrational for these designs.

Real-World Case Studies in Repairability

The feasibility of EV battery repair is not a hypothetical discussion; it is a reality shaped by specific OEM design choices. Case studies demonstrate a clear and growing dichotomy in the industry’s approach to serviceability.

Modular Architectures (Nissan Leaf, Chevy Bolt, Hyundai/Kia)

Many early-generation EVs were designed with a modular approach, which unintentionally created a pathway for repair and a burgeoning aftermarket.

Nissan Leaf: The passive-cooled packs in older Nissan Leaf models have been successfully serviced by independent repair shops. These shops have developed a business around refurbishing and upgrading packs by swapping out degraded modules, demonstrating that module-level repair is both technically possible and economically viable.
Chevy Bolt: GM’s recall of the 2017-2022 Bolt EV and EUV is a prime example of a mass, OEM-sanctioned module replacement. The root cause of the fire risk was a rare manufacturing defect in a single cell, but the official remedy was the replacement of the entire affected battery module, not individual cells. This highlights that for this modular design, the module was the designated serviceable unit.
Hyundai/Kia: Similar to GM, Hyundai issued a recall for the Kona Electric that resulted in a full battery replacement. However, newer models like the Kia EV9 are being designed with features like “access plates for serviceable items” such as the BMS, suggesting that manufacturers are now considering some level of component repairability.

Integrated and Structural Packs (Tesla, BYD)

In stark contrast to the modular approach, some manufacturers are moving towards a fully integrated design, which eliminates repairability as a design consideration.

Tesla (4680 Structural Pack): Teardowns of Tesla’s 4680 structural battery pack reveal a design with “zero repairability”. The pack is so tightly integrated that if it fails, it is “destined for the crusher”. A teardown report described the process as a “reclamation project” for recyclers, indicating that any attempt at repair would be a destructive process.
BYD (Blade Battery): Teardowns of the BYD Blade pack similarly show a design that is optimized for durability and safety but not for serviceability. The cells are connected with laser-welded busbars and secured with extensive, unforgiving adhesives. To access the cells, teardown experts had to cut into the pack’s enclosure with a metal saw, confirming that the pack was not designed for non-destructive, field-level repair.

The Indian Market Perspective (Tata Nexon EV)

Anecdotal evidence from EV owners in India highlights the real-world friction between repairability and warranty claims. Owners of the Tata Nexon EV have reported a common issue of sudden State of Charge (SOC) drops. While service centers initially attempted to fix the issue with software updates or cell replacement, these problems have been reported to return. As a result, some owners claim that warranty claims were denied by the manufacturer citing minor dents or scratches on the battery casing, effectively shifting the financial burden to the customer’s insurance. This demonstrates that without a robust, OEM-sanctioned repair ecosystem, owners can be left in a legal and financial limbo.

Safety, Risk, and Legal Considerations

Working on a high-voltage EV battery pack is an extremely dangerous undertaking that is not comparable to servicing a traditional internal combustion engine. The legal and financial implications are as complex as the technology itself.

Critical Safety Protocols

EV batteries operate at voltages of 400V or higher, posing a significant risk of electrocution. As such, any work on the pack must be performed by a trained professional who adheres to strict safety protocols.

Personal Protective Equipment (PPE): Non-negotiable safety gear includes insulated Class 0 rubber gloves, face shields, and flame-retardant clothing.
Lockout-Tagout (LOTO): A systematic procedure is required to de-energize the high-voltage system and ensure it cannot be accidentally re-engaged while work is being performed.
Wait Time: A mandatory waiting period of at least 15 minutes after the high-voltage system is disconnected is necessary to allow any residual voltage to dissipate.

The Right-to-Repair Landscape

The legal landscape surrounding EV battery repair is a patchwork of policies that are often in conflict with the technical realities of the product.

US Perspective: While states like California and New York have enacted broad “Right to Repair” laws, most of them explicitly exempt motor vehicles due to safety and security concerns. The notable exception is Massachusetts, which has a specific law for automotive repair.
EU Perspective: The new EU Batteries Regulation (2023) and the Right to Repair Directive (2024) are more comprehensive. The directive aims to promote repair by obligating manufacturers to provide access to spare parts and repair information at a “reasonable price” and by prohibiting contractual clauses that impede repair. However, the application of this directive to the highly integrated nature of modern EV battery packs remains to be seen.

Warranty, Liability, and Insurance

Beyond the safety risks, independent EV battery repair carries significant legal and financial consequences.

Warranty Voiding: EV batteries are protected by long-term warranties, typically 8 years or 100,000 miles, with a guarantee that the battery will retain at least 70% of its original capacity. Any repair or modification performed outside of an authorized dealer, or with non-approved parts, can be used as grounds to void this warranty.
Liability: In the event of an accident or fire, determining liability for a pack that was independently repaired can be a legal and logistical nightmare. The liability may fall on the vehicle manufacturer, the battery manufacturer, or the independent repair shop, depending on the cause of the failure.
Insurance: While most comprehensive auto insurance policies cover battery replacement in the event of an accident, they may not cover failures caused by improper independent repairs.

Economic and Environmental Verdict

The high cost of a new EV battery pack is a major concern for consumers, but it is often a psychological barrier rather than a practical one. A deeper analysis of the economics and environmental impact reveals a more nuanced picture.

Cost-Benefit Analysis

The upfront cost of a full EV battery pack replacement is substantial. A survey of US mechanics found that the average cost to replace a battery for a 2014 Tesla Model S was approximately $15,000, while a 2014 Nissan Leaf replacement averaged around $17,657. A Tata Nexon EV battery in India was quoted at Rs. 7,00,000, a significant portion of the vehicle’s total cost.

However, this sticker shock is mitigated by several factors. The cost is overwhelmingly driven by the price of the battery itself, with labor being a relatively smaller portion of the total expense. More importantly, the possibility of this “worst-case scenario” is statistically insignificant. A study found that across all models and years, only 2.5% of non-recalled batteries have been replaced. The cost of a full pack must also be weighed against the significant savings in maintenance and fuel over an ICE vehicle’s lifespan.

Long-Term Reliability

The notion that EV batteries will fail en masse after a few years is a myth. Modern EV batteries are engineered for durability, with an average degradation rate of just 2.3% per year. Data from thousands of vehicles shows that they typically retain 80-90% of their capacity after 8-10 years and over 100,000 miles, far exceeding the lifespan of many other vehicle components. The widespread adoption of 8-year/100,000-mile warranties is a strong signal of manufacturer confidence in battery longevity.

The Sustainability Equation (Reuse vs. Recycling)

The long-term sustainability of the EV industry depends on a robust ecosystem for battery end-of-life management.

Reuse (Second-Life): A battery that has degraded to 70-80% of its original capacity may be at its automotive “end-of-life,” but it is often perfectly suited for a less demanding second-life application, such as stationary energy storage for home solar systems. A study found that using a battery for a second life has a greater short-term carbon footprint benefit than immediate recycling.
Recycling: When a battery is no longer useful, recycling is critical to recover valuable materials like lithium, cobalt, and nickel, reducing the need for environmentally damaging mining. Major recyclers are already achieving recovery rates of over 90%.

The ultimate solution is a systemic approach that combines both strategies—reusing batteries for a second life where possible and then recycling them to recover materials for new batteries.

Conclusion & Final Verdict

Can you replace individual cells in an EV battery pack? The answer is a qualified “yes,” but only under a specific and shrinking set of conditions. For older, modular-style EV batteries, a professional technician with the right tools and expertise can and does perform cell or module replacements. These repairs are both technically feasible and, in some cases, economically rational.

However, for the majority of new EVs on the market, particularly those with CTP or structural pack designs, the answer is a practical “no.” The risks of thermal runaway, electrical imbalance, and voided warranties, coupled with the mechanical impossibility of non-destructive disassembly, make such a repair a high-stakes gamble that is rarely justified. The decision to prioritize manufacturing efficiency, durability, and energy density has created a product that, by design, is not intended for field-level component repair.

The future of battery repair will likely not be about individual cells but about the creation of a professional, certified aftermarket that can safely replace and refurbish entire modules and packs, working in collaboration with OEMs. The long-term sustainability of the industry depends on a robust ecosystem that can give these batteries a second life and a proper recycling process at the end of their service.

Call-out Boxes

Safety Tip: Always assume an EV battery is energized. Use proper Personal Protective Equipment (PPE) and follow Lockout-Tagout (LOTO) procedures. A mandatory 15-minute wait time is required after the high-voltage system is disconnected to allow residual voltage to dissipate.

Pro Insight: A new, high-capacity cell is an electrical anomaly in an aged pack. Installing it without careful matching of capacity and internal resistance can lead to overcharging and accelerated degradation of the entire system, making a seemingly simple fix a recipe for a more significant failure.

Myth vs. Fact: Myth: All EV batteries will fail after 8-10 years, making EVs too expensive to own. Fact: Modern EV batteries are engineered to last. The average degradation is only 2.3% per year, and most packs retain 70-90% of their capacity after 8-10 years, far exceeding the lifespan of many other vehicle components. The high cost of a replacement is a rare, worst-case scenario.

Comparison Tables

Chemistry	Pros	Cons
NMC/NCA	High energy density (more range) , better cold-weather charging , common in performance EVs	More expensive due to cobalt/nickel , shorter cycle life (~1,000-2,000 cycles) , higher thermal runaway risk
LFP	Lower cost , superior safety (less thermal runaway risk) , longer cycle life (>3,000 cycles)	Lower energy density (less range) , more sensitive to cold temperatures

OEM	Design Philosophy	Repair & Serviceability
Chevy Bolt (pre-2023)	Modular (Cell-to-Module)	OEM recalls led to module-level replacements
Nissan Leaf (Gen 1)	Modular (Cell-to-Module)	Independent aftermarket has developed successful module replacement services
Tesla (4680 Structural)	Integrated (Cell-to-Body)	Described as having “zero repairability” and is a “reclamation project” for recyclers if it fails
BYD (Blade)	Integrated (Cell-to-Pack/Body)	Disassembly requires cutting into the pack due to extensive adhesives and welded joints

Risk	Likelihood	Impact	Mitigating Factor
Electrocution	Low (for trained pros)	Catastrophic	Strict adherence to high-voltage safety protocols, PPE, and LOTO
Thermal Runaway	Low	Catastrophic	Proper thermal management, cell matching, and use of safe handling procedures
Electrical Imbalance	High	Significant	Meticulous cell matching and conditioning, followed by BMS recalibration
Warranty Voiding	High	Significant	Use OEM-certified service centers and parts to maintain warranty
Legal Liability	Moderate	Significant	Requires professional certification and insurance to cover potential legal claims

Technician Checklist

1. Preparation & Safety:
- PPE: Insulated Class 0 rubber gloves, face shield, and flame-retardant clothing.
- LOTO: Implement the full lockout-tagout procedure to de-energize the high-voltage system.
- Wait Time: Observe the mandatory 15-minute waiting period to allow residual voltage to dissipate.
2. Diagnostics:
- Initial Check: Scan the vehicle for Diagnostic Trouble Codes (DTCs) from the BMS.
- Visual Inspection: Check for any physical signs of damage, swelling, or leaks.
- Thermal Scan: Use a thermal camera to identify hotspots or temperature anomalies.
- Electrical Test: Measure individual cell/module voltages and conduct a DCIR test to pinpoint weak cells.
3. Repair & Replacement:
- Matching: If replacing cells, use a single-cell tester to match replacement cells based on capacity and internal resistance to the rest of the pack.
- Connections: Use specialized, insulated tools for all connections. Use a spot welder for cell tabs where applicable.
- Sealing: Re-seal the pack with a manufacturer-approved sealant or gasket to maintain its ingress protection (IP) rating.
4. Post-Repair Testing:
- Insulation Resistance: Perform a full insulation resistance test with a megohmmeter to verify system integrity.
- Balancing: Reconnect the pack and confirm that the BMS is properly balancing cell voltages.
- BMS Recalibration: Perform a BMS reset or conditioning cycle to resynchronize the system with the new cell/module.

FAQs

Q: What is the average lifespan of an EV battery?
- A: Modern EV batteries are built to last. A study found the average capacity loss is just 2.3% per year. Most batteries are engineered to retain 70-80% of their original capacity after 8-10 years or 100,000+ miles.
Q: Can a new EV battery cell be a “bad” replacement for an old pack?
- A: Yes. A new cell has a higher capacity and lower internal resistance than an aged cell. This electrical mismatch can cause imbalances in the pack, leading to overcharging of the new cell and over-discharging of the old ones, which can accelerate degradation.
Q: How does a structural battery pack affect repairability?
- A: Structural packs, like those in some modern Tesla and BYD models, integrate the battery into the vehicle’s chassis. This design, while improving vehicle rigidity, makes the pack a monolithic, non-serviceable component that is often considered to have “zero repairability” in the field.
Q: What is the purpose of a BMS?
- A: The Battery Management System is the brain of the battery pack. It monitors and controls key parameters such as voltage, temperature, and current to ensure safety, optimize performance, and extend the battery’s lifespan. It is responsible for balancing cell voltages.
Q: Why do some EV batteries use adhesives and potting compounds?
- A: Industrial-grade adhesives and potting compounds are used to enhance safety, extend battery life, and optimize performance. They secure the cells, improve thermal management by conducting heat away from cells, and mitigate the propagation of thermal runaway.
Q: How does an EV battery recall affect repair?
- A: In the case of the Chevy Bolt recall, the OEM (GM) addressed a manufacturing defect by replacing the entire battery module, not individual cells. This demonstrates that for modular packs, the module is the intended serviceable unit.
Q: What is the average cost of a full EV battery replacement?
- A: The average cost for a full pack replacement varies significantly by model, with estimates for older vehicles like a 2014 Tesla Model S and Nissan Leaf averaging between $15,000 and $17,657. The cost is primarily driven by the price of the battery itself, which can exceed $10,000.
Q: Is a new, high-capacity cell a risk for an old pack?
- A: Yes. A new cell has a significantly higher capacity and lower internal resistance (IR) than an aged cell, causing imbalances that can overcharge the new cell and over-discharge the older ones. This can lead to a domino effect of degradation in the entire pack.

Glossary

Anode: The negative electrode of a battery cell where electrons are released during discharge.
Battery Management System (BMS): The electronic “brain” that monitors and manages the battery pack’s performance, safety, and health. It controls parameters such as voltage, temperature, and cell balancing.
Binning: The process of sorting battery cells by matched characteristics, such as capacity, voltage, and internal resistance, to ensure they perform consistently when assembled into a pack.
Busbar: A metallic strip or bar that conducts electricity. In EV battery packs, busbars connect individual cells or modules, often via laser welding, to create series or parallel circuits.
Cathode: The positive electrode of a battery cell where electrons re-enter during discharge.
Cell-to-Body (CTB): A design philosophy where battery cells are integrated directly into the vehicle’s chassis, making the pack a structural component.
Cell-to-Pack (CTP): A design approach that eliminates the module structure, placing cells directly into the battery pack housing to increase energy density and simplify manufacturing.
Cylindrical Cell: A battery cell encased in a cylindrical metal tube, commonly used in sizes like the 18650, 21700, and 4680.
DCIR (Direct Current Internal Resistance): A measure of a battery cell’s internal resistance, which increases with age and degradation. It is a key indicator of cell health.
Kilowatt-hour (kWh): The unit of energy capacity for an EV battery, representing the amount of power (in kilowatts) that can be delivered over one hour.
LFP (Lithium Iron Phosphate): A battery chemistry known for its low cost, high safety, and long cycle life, but with a lower energy density than NMC or NCA.
Lockout-Tagout (LOTO): A safety procedure used to ensure that dangerous equipment, such as a high-voltage battery, is properly shut off and cannot be started up again prior to the completion of maintenance or repair work.
Megohmmeter (Megger): A specialized electrical instrument used to measure the insulation resistance of high-voltage components, a critical safety test for EV batteries.
Module: An intermediate assembly of multiple battery cells. In a traditional battery pack, multiple modules are combined to form the complete pack.
NCA (Lithium Nickel Cobalt Aluminum Oxide): A battery chemistry with high energy density, similar to NMC, primarily used in Tesla’s older vehicles.
NMC (Lithium Nickel Manganese Cobalt Oxide): A common battery chemistry in modern EVs, valued for its high energy density and performance.
Potting Compound: An epoxy or polyurethane resin used to encapsulate and protect electronic components, such as battery cells, to enhance structural integrity, thermal management, and safety.
Pouch Cell: A battery cell encased in a flexible, laminate pouch, offering high energy density at the cell level due to its flexible, lightweight casing.
Prismatic Cell: A battery cell encased in a rigid, rectangular metal box, offering high packing efficiency.
Right-to-Repair: A legal and political movement advocating for consumer access to the tools, parts, and information needed to repair their own products.
Thermal Runaway: A dangerous condition where a battery cell’s internal temperature rapidly increases, leading to a chain reaction of exothermic events that can result in fire or explosion.
UN 38.3: A set of international standards and regulations for the transport of lithium-ion batteries, particularly regarding safety and testing procedures.