How to Use This Glossary
Battery documents mix engineering terms, trade abbreviations and a few marketing habits, and two suppliers can use the same word for different measurements. This battery glossary collects the terms as they appear in datasheets, quotations and project discussions, in plain language and without formulas beyond the arithmetic a buyer actually needs. When a supplier's use of a term differs from the definition here, ask for the definition in writing and file it with the quotation, because most later disputes are definitions that were never written down.
The Terms, Alphabetically
| Term | Meaning |
|---|---|
| Active material | The compound in the electrodes that stores lithium; its quality drives capacity and cycle life |
| Ampere-hour (Ah) | The charge a battery can deliver; a 100 Ah pack delivers 5 A for about 20 hours at rated conditions |
| Battery management system (BMS) | The electronics that monitor cells and protect against overcharge, over-discharge, over-current, short circuit and out-of-range temperatures |
| CAN bus | A communication interface over which the BMS reports status to an inverter or site controller |
| C-rate | Current expressed against capacity; 0.5C on a 100 Ah pack is 50 A |
| Capacity | The ampere-hours a pack delivers under a stated rate, temperature and cut-off voltage |
| Cathode and anode | The positive and negative electrodes of a cell during discharge |
| Cell | The single electrochemical unit; packs are built from cells in series and parallel |
| Charge voltage | The voltage a charger must reach and hold to fill the pack; around 14.6 V is typical for a 12.8 V LiFePO4 pack |
| Cycle life | The number of charge and discharge cycles a pack delivers before capacity falls to a stated end point, such as 80 percent |
| Depth of discharge (DOD) | The share of capacity removed in a cycle; deeper daily discharge consumes cycle life faster |
| Electrolyte | The medium that carries lithium ions between the electrodes |
| Energy density | Energy per unit mass or volume, in watt-hours per kilogram or per liter |
| Float voltage | A holding voltage applied after charge in lead-acid practice; LiFePO4 generally does not need float |
| Formation | The initial controlled charge cycles that prepare new cells for service |
| Internal resistance | The opposition a pack offers to current; higher resistance means more heat and more voltage sag |
| Kilowatt-hour (kWh) | One thousand watt-hours; nominal voltage times ampere-hours divided by 1000 |
| LiFePO4 | Lithium iron phosphate, the cathode chemistry used across this catalog, valued for stability and cycle life |
| Nominal voltage | The representative pack voltage; 12.8 V, 25.6 V and 51.2 V for 4, 8 and 16 LiFePO4 cells in series |
| NMC | Nickel manganese cobalt oxide, an energy-dense chemistry used where weight matters most |
| OEM and ODM | Original equipment manufacturing, where the buyer brands the supplier's product; original design manufacturing adds supplier-led design work |
| Parallel connection | Connecting packs positive to positive to add capacity and current capability at the same voltage |
| Peak power | The short-term power a pack can deliver above its continuous rating, for starts and surges |
| RS485 | A serial communication standard commonly used between BMS, inverters and monitoring systems |
| Self-discharge | The slow loss of charge when a pack stands idle; low in LiFePO4 chemistry |
| Semiconductor fuse | A fast-acting protective device used where high current must be interrupted quickly |
| Separator | The membrane that keeps the electrodes apart while passing lithium ions |
The Terms, Alphabetically, Continued
| Term | Meaning |
|---|---|
| Series connection | Connecting cells end to end to add voltage; sixteen cells in series make a 51.2 V pack |
| State of charge (SOC) | The remaining capacity as a percentage of current full capacity |
| Thermal runaway | A self-sustaining overheating failure; LiFePO4 chemistry resists its onset compared with layered oxides |
| UN 38.3 | The United Nations transport test series a lithium battery must pass before it can ship |
| Usable capacity | The capacity available between the BMS cut-offs in real operation, always less than rated capacity |
| Watt and watt-hour (W, Wh) | Units of power and energy; a 100 W load run for 3 hours uses 300 Wh |
Where the Terms Meet the Catalog
Used together, the terms above describe any pack a quotation can offer. A datasheet line such as 12.8 V, 100 Ah means a four-cell LiFePO4 pack holding about 1.28 kWh, and the same reading applied to a 51.2 V line explains why a 200 Ah model carries four times the energy. Reading quotations this way turns comparison into arithmetic instead of impression.
Where YueQi Fits
YueQi New Energy, based in Zhongshan, Guangdong, publishes datasheets for its LiFePO4 storage range in the vocabulary above: 12.8V, 25.6V and 51.2V battery packs, integrated home storage units and portable power stations. Where any term in a datasheet needs a written definition for a contract or a tender file, the company provides it on request, and definitions specific to a project are to be confirmed in writing alongside the quotation.
Next step
Send your application, target specification and estimated quantity with your inquiry, and we will confirm matching products, samples and document requirements in writing. See the product lines or request a quote.