The root cause of gas production in lithium batteries is essentially the result of a series of unwanted chemical and electrochemical side reactions inside the battery. These reactions consume the active ingredients in the battery and generate gaseous products, leading to a decrease in battery performance and even causing safety issues.  The gas production of lithium batteries mainly comes from the following aspects:1. Electrolyte decompositionWhen used improperly at high temperatures or voltages (such as overcharging), organic solvents in the electrolyte can undergo oxidation or reduction reactions and decompose. The main gases are:Carbon dioxide (CO ₂), carbon monoxide (CO), methane (CH ₄), ethylene (C ₂ H ₄), etc. two SEI film damage and recombination.2. SEI film damage and recombinationIf the SEI protective film on the negative electrode surface ruptures due to overcharging, overdischarging, or high temperature, the electrolyte will directly react with the negative electrode material in an attempt to repair the SEI film, and this process will continuously generate gas.The main gases are:Hydrogen (H ₂), ethylene (C ₂ H ₄), ethane (C ₂ H ₆), etc.3. Excessive moisture contentEven trace amounts of water (ppm level) can react with lithium salts (such as lithium hexafluorophosphate LiPF ₆) in the electrolyte, generating corrosive hydrofluoric acid (HF) and further triggering side reactions to produce gas. The main gases are:Hydrogen (H ₂), hydrogen fluoride (HF), carbon monoxide (CO), carbon dioxide (CO ₂).4. Side reactions of positive electrode materialsUnder overcharging or high temperature, the structure of positive electrode materials (especially high nickel ternary materials) may collapse, releasing oxygen. The released oxygen will oxidize the electrolyte, producing more gas. The main gases are:Oxygen (O ₂), carbon dioxide (CO ₂).5. Negative electrode material side reactionsFor materials such as silicon anodes, significant volume changes during charge and discharge can repeatedly damage the SEI film, leading to sustained side reactions and gas production. Under excessive discharge or high temperature, the graphite negative electrode will also react with the electrolyte. The main gases are:Hydrogen (H ₂), Ethylene (C ₂ H ₄), Ethane (C ₂ H ₆).

We often see in the media and online that a certain company has made a huge breakthrough in solid-state batteries. Alternatively, a company may announce the mass production of solid-state batteries by 202X. Perhaps they only dare to say that it is a solid-state battery, and dare not say that their battery is an all solid state battery.Solid state batteries can simply include (semi-solid, quasi solid, and all solid state batteries), and in order to appear high-end and attract attention, they directly refer to solid-state batteries.What is the difference between the three?The core difference between semi-solid, quasi solid, and all solid state batteries lies in the physical state of the electrolyte, ion conductivity, interface issues, and industrial maturity.The following comparison chart can clearly summarize the core differences and evolutionary relationships among the three:Detailed explanation of core differences1. All solid state batteryElectrolyte state: 100% solid, without any liquid electrolyte. Solid electrolytes such as oxides, sulfides, or polymers are usually used.  Key features:Highest safety: completely eliminate the risks of leakage, combustion, and explosion (especially when using metal lithium negative electrodes).The maximum potential for energy density: compatible with high-voltage positive electrodes and metal lithium negative electrodes, theoretically with an energy density of over 500 Wh/kg.  The interface problem is the most severe: solid solid contact leads to high interface impedance, difficult ion transport, and the biggest challenges are rate performance and cycle life.  Cost and process are extremely difficult: the preparation process is complex (such as the processing of brittle electrolytes, thin film preparation), the cost is extremely high, and mass production is the most difficult.  Current situation: In the research and development and pilot stage, it is widely recognized as the "ultimate solution", but the road to commercialization is the longest. Representative companies: Toyota, QuantumScape。2. Quasi solid state batteriesElectrolyte state: "quasi solid" or "gelled", containing a small amount (usually<5%) of liquid electrolyte or plasticizer, wetting the space between solid electrolyte particles with a very small amount of liquid.  Key features:Transitional solution: It can be seen as a preparatory form of all solid state battery. It sacrifices "absolute solid state" in exchange for more feasible interface performance.  Interface improvement: Trace amounts of liquid greatly enhance the ion transport capability of the solid solid interface and reduce interface impedance.  Performance Balance Point: Seeking a feasible balance between safety, energy density, and electrochemical performance. Its energy density and safety are still significantly higher than liquid state batteries, but slightly inferior to ideal all solid state batteries.  The manufacturing process is relatively friendly: closer to existing production lines than all solid state.  Current situation: Often overlapping or mixed with the concept of "semi-solid", it is a crucial step for many enterprises to move from semi-solid to all solid state.3. Semi solid state batteriesElectrolyte state: solid-liquid mixture, coexistence of solid electrolyte and liquid electrolyte, with high liquid content (usually>5%, even up to 10-20%).  Key features:Compromise and improvement plan: Essentially, it is a "heavy improvement" of existing liquid lithium-ion batteries, rather than a subversion. Solid electrolyte coatings or composites with electrode materials are commonly used.  Improved safety: The quality of liquid electrolysis has been reduced, reducing the risk of combustion, but it has not been completely eradicated.  Significant improvement in energy density: High capacity positive and negative electrode materials (such as high nickel and silicon carbon) can be partially applied, with an energy density of 300-400 Wh/kg.  Compatible with existing production lines: The production process adjustment is relatively small, making it the first route to achieve commercial mass production.  There is still a risk of leakage: essentially still belongs to the category of "liquid batteries".Current situation: It has entered the stage of mass production and installation. Representative applications: NIO's 150kWh semi-solid battery pack (Weilan New Energy), Lantu Chasing Light (Ganfeng Lithium), etc.

Due to the differences in voltage, capacity, charge capacity, internal resistance, discharge plateau, and constant current ratio among the individual cells, the charging and discharging rates of the battery module composed of individual cells cannot be synchronized and consistent during charging and discharging, which will shorten the service life of the entire battery module.Therefore, separate capacity treatment must be carried out to make the single battery of the same module have the same voltage; Consistent cycle life; Consistent capacity; Consistent self discharge; Consistent electrical charge; Consistent internal resistance; Consistent discharge platform; Consistent constant current ratio.Consistent voltage:① Inconsistent voltage in series circuits can cause overcharging and overdischarging, and the manager cannot control the battery system; ② The parallel circuit voltage is not consistent, and the batteries are charged and discharged evenly between each other until the voltage is consistent. But if the pressure difference between them is too large, the fuse (PCB board structure) will be blown, and the fuse is allowed to have a pressure difference of less than 0.6V;③ If there is a large pressure difference between the series modules, it can only be resolved through active balancing by BMS. In severe cases, manual charging and discharging or removal of faulty batteries by after-sales service is required.2. Consistent capacity:Inconsistent capacity is the main cause of voltage inconsistency, and there is a risk of overcharging and overdischarging during the charging and discharging process.3. Consistent electrical charge:Even if the battery capacity is the same, if the charged amount is not the same, it can still cause overcharging and overdischarging phenomena.4. Consistent internal resistance:Each individual physical battery can theoretically be divided into two parts: a pure battery and an internal resistance, and inconsistent internal resistance will cause asynchronous charging and discharging of the pure battery.

We know that a car's battery is composed of many battery cells. Generally, modules are composed of battery cells, and the modules form a PACK. For example, the Tesla Model S's battery system is carefully composed of 7104 18650 lithium batteries. The Xiaomi SU7 Max battery pack is composed of 198 battery cells connected in series. With so many battery cells, if one of them is faulty, it's easy to carry the whole into the ditch. As a familiar saying goes, "A piece of mouse dung will kill a pot of porridge". So the consistency of battery cells in power batteries is very important. 1、 The harm caused by poor consistencyPoor consistency of battery cells in power batteries can cause various hazards, directly affecting battery performance, safety, lifespan, and overall vehicle reliability. The following is a specific analysis of hazards and mechanisms:① Capacity degradation and battery life decreaseShortboard effect: In cells with poor consistency, the unit with the lowest capacity will be the first to fully charge or empty, resulting in the overall available capacity of the battery pack being limited by the "weakest cell".Example: If the capacity of a certain battery cell is 10% lower than others, the entire battery pack capacity may be lost by 5% to 8%, significantly reducing the vehicle's range. ② Safety hazards: thermal runaway, fire and explosionRisk of overcharging/overdischarging: When the voltage is inconsistent, some cells may be forcibly charged to overvoltage (>4.3V) or discharged to undervoltage (<2.5V), causing lithium dendrite growth, piercing the diaphragm and causing internal short circuit, ultimately leading to thermal runaway.Uneven heat distribution: Cells with large internal resistance or temperature differences overheat locally during charging and discharging, forming "hotspots" and accelerating heat diffusion. ③ Significantly shortened battery lifeAging acceleration: Cells with poor consistency are subjected to uneven loads during cycling. For example, repeated overdischarging of low capacity cells can accelerate the decay of electrode materials, potentially shortening their lifespan by 30% to 50%.Chain reaction: The failure of a single battery cell (such as a sudden drop in capacity) will force other battery cells to compensate, exacerbating overall aging. ④ Failure of Battery Management System (BMS)SOC/SOH estimation distortion: BMS relies on cell parameter consistency for precise management. If the difference in battery cells is too large, BMS may not be able to accurately estimate the remaining state of charge (SOC) or state of health (SOH), and may misjudge the battery status.Overload of balancing function: BMS needs to frequently balance cells with significant differences, resulting in increased energy consumption and limited effectiveness, ultimately leading to overload or failure of the balancing circuit.2、 How to screen out cells with poor consistencyThe following are the methods and steps for consistency screening of battery cells:① Voltage matching: That is, OCV testing measures the open circuit voltage (OCV) of the battery cell after it has been idle (usually 24-48 hours), and eliminates cells with voltage deviations exceeding the set threshold (such as ± 5mV).② Capacity sorting: Obtain the actual capacity of the battery cells through charge and discharge tests, and divide them into capacity intervals (such as ± 1%) to ensure that the difference in battery cell capacity within the same battery pack is minimized. ③ Internal resistance screening: Measure the DC internal resistance (DCR) or AC internal resistance (ACR), and remove cells with high internal resistance or large dispersion (such as internal resistance deviation>3%). ④ Self discharge rate (K value) test: After fully charging the battery cell, let it stand for 7-14 days, calculate the self discharge rate (K value) based on the voltage drop, and screen for cells with similar K values (such as K value difference<0.5%). The role of K=(OCV1- OCV2)/(t2- t1) K value testing should not be underestimated.⑤ Aging and cycle testingHigh temperature aging screening: Place the battery cells in a high-temperature environment (such as 45 ℃) and monitor the voltage decay rate to screen for cells with consistent aging characteristics. Cycle life pre-test: Perform a small amount of charge and discharge cycles on the battery cell (such as 50 times) to eliminate cells with abnormal capacity decay or sudden internal resistance changes.When selecting power batteries, the quality of the battery cells will greatly affect the performance of the entire battery pack, so it is necessary to conduct strict inspections of product quality and suppliers in the early stage. As a professional lithium battery supplier，Be Power is committed to providing customers with high-quality and customized solutions；We are the number one Chinese battery supplier delivered to automotive OEM in Brazil.We offered battery for over 800K set HESS systems;We are the best UTV battery supplier and exporter in China, with over 15 years of experience in lithium battery research and development.We are the best battery pack solutions provider in China.Our battery systems are warmly welcomed in over 30 countries applied on electric trucks，electric light vehicles，electric UTV, electric sweepers, container energy storage systems, 215Kwh commercial and industrial energy storage systems etc. With top-notch technical team in China we are providing the toughest technical and highest level safety products.

Great Power has been listed as a BNEF Tier1 global first tier energy storage manufacturer for four consecutive times! Recently, Bloomberg NEF (Bloomberg New Energy Finance, abbreviated as BNEF), a globally renowned research institution, officially released the Global Tier 1 Energy Storage Tier 1 List 2Q 2025 for the second quarter of 2025.BNEF rigorously evaluates project scale, technological innovation, supply chain resilience, financial health, and global market influence from multiple dimensions. Every year, only the top energy storage companies with comprehensive strength are selected to enter the Tier 1 list. Its rating results are regarded as industry benchmarks by global energy giants, investment institutions, and governments.Great Power has made a strong breakthrough among global energy storage companies with its innovative product technology, leading intelligent manufacturing, efficient global delivery system, and full cycle project execution control capabilities. It has been ranked as a BNEF Tier 1 global first level energy storage manufacturer for four consecutive times, marking Great Power's continuous recognition of its comprehensive strength by international authorities！As the overseas partner of Great Power, Be Power is committed to providing customers with high-quality and customized solutions；We are the number one Chinese battery supplier delivered to automotive OEM in Brazil.We offered battery for over 800K set HESS systems;We are the best UTV battery supplier and exporter in China, with over 15 years of experience in lithium battery research and development. Our battery systems are warmly welcomed in over 30 countries applied on electric trucks，electric light vehicles，electric UTV, electric sweepers, container energy storage systems, 215Kwh commercial and industrial energy storage systems etc. With top-notch technical team in China we are providing the toughest technical and highest level safety products!

The importance of voltage consistency in lithium batteries.The voltage consistency of lithium batteries refers to the ability of individual lithium batteries in the same batch or system to maintain consistent terminal voltage under the same operating conditions. Voltage consistency has a crucial impact on the performance, lifespan, and safety of lithium battery packs. 1. Voltage consistency is related to the overall performance of lithium battery packs.In a battery pack, if there is a voltage difference between individual cells, some cells may reach their upper or lower voltage limit in advance during the charging and discharging process, resulting in the entire battery pack not being able to fully utilize its capacity, thereby reducing overall energy efficiency.2. Voltage consistency has a direct impact on the safety of lithium batteries.When the voltage of individual cells in the battery pack is inconsistent, some cells may experience thermal runaway due to overcharging or overdischarging, leading to safety accidents such as fires or explosions. 3. Voltage consistency also affects the lifespan of lithium batteries. Due to inconsistent voltage, some individual cells in the battery pack may experience more charge and discharge cycles, leading to a shortened lifespan and ultimately affecting the overall service life of the battery pack.The impact of inconsistent voltage on lithium batteries1. Performance degradation: The voltage difference between individual cells can lead to a decrease in the overall performance of the battery pack. During the discharge process, batteries with lower voltage will limit the discharge voltage and capacity of the entire battery pack, thereby reducing the energy output of the battery pack. 2. Unbalanced charging and discharging: Inconsistent voltage can cause uneven charging and discharging of the battery pack. Some batteries may be fully charged or emptied in advance, while others may not have reached their charging and discharging limits, which can lead to a decrease in the overall capacity utilization of the battery pack. 3. Risk of thermal runaway: Inconsistent voltage may increase the risk of thermal runaway in the battery pack. Overcharged or overdischarged batteries may generate a large amount of heat. If the heat is not dissipated in a timely manner, it may cause thermal runaway of the battery and result in safety accidents. 4. Shortened lifespan: Inconsistent voltage can lead to increased differences in the lifespan of individual cells within the battery pack. Some batteries may fail prematurely due to excessive charging and discharging, thereby affecting the lifespan of the entire battery pack.How to improve the voltage consistency of lithium batteries1. Strengthen battery management system: Battery management system (BMS) is the key to ensuring battery voltage consistency. By monitoring and adjusting the voltage between battery cells in real-time, BMS can ensure that the battery pack maintains voltage consistency during charging and discharging processes. In addition, BMS can also achieve balanced management of battery packs, avoiding overcharging or overdischarging of individual batteries. 2. Implement regular maintenance and calibration: Regular maintenance and calibration of lithium battery packs can maintain voltage consistency between battery cells. For example, regular charging and discharging calibration of battery packs can ensure that each battery cell reaches the same charging and discharging state, thereby improving voltage consistency. 3. Adopting advanced battery balancing technology: Battery balancing technology is an effective means of improving battery voltage consistency. By actively or passively balancing, the voltage difference between battery cells can be reduced to an acceptable range, ensuring that the battery pack maintains voltage consistency during charging and discharging processes. 4. Improve the usage environment: The usage environment also has a certain impact on the voltage consistency of lithium batteries. By improving the usage environment of batteries, such as reducing temperature fluctuations, minimizing vibration and shock, the impact of environmental factors on battery performance can be reduced, thereby maintaining battery voltage consistency.ConclusionThe voltage consistency of lithium batteries has a significant impact on the performance, safety, and lifespan of battery packs. Inconsistent voltage may lead to performance degradation, uneven charging and discharging, increased risk of thermal runaway, and shortened lifespan of the battery pack. Therefore, improving the voltage consistency of lithium batteries is crucial. Choosing products from high-quality and reliable battery manufacturers can effectively ensure the voltage consistency of lithium batteries, thereby ensuring the safe, stable, and efficient operation of battery packs.Be Power is committed to providing customers with high-quality and customized solutions；We are the number one Chinese battery supplier delivered to automotive OEM in Brazil.We offered battery for over 800K set HESS systems;We are the best UTV battery supplier and exporter in China, with over 15 years of experience in lithium battery research and development.We are the best battery pack solution provider in China.Our battery systems are warmly welcomed in over 30 countries applied on electric trucks，electric light vehicles，electric UTV, electric sweepers, container energy storage systems, 215Kwh commercial and industrial energy storage systems etc. With top-notch technical team in China we are providing the toughest technical and highest level safety products.