If you source wrapping film for lithium battery PACK, you will meet three product forms again and again: PVC heat shrink flat film, finished lay-flat sleeves, and upgraded insulation film. They are made from related materials, but they sit at very different points of the supply chain — and buying the wrong one wastes both tooling and lead time. This guide explains, in plain terms, which one fits your project.给锂电池 PACK 采购包膜时，你会反复遇到三种产品形态：PVC 热缩平膜、成品对折套管和升级款绝缘膜。它们材料相近，却处在供应链完全不同的位置——买错形态，既费设备又拖交期。这篇用最直白的方式讲清：你的项目到底该选哪一种。
1. Flat film: the master-roll substrate一、平膜：母卷基材
Flat film is a calendered PVC master roll, non-folded and supplied in wide rolls (commonly 10–1600 mm, thickness 0.05–0.20 mm). It is the upstream raw material. You slit it, print it and — if you make your own tubes — form it into sleeves before wrapping.平膜是压延 PVC 母卷，不对折、宽幅供货（常见 10–1600mm，厚度 0.05–0.20mm），属于上游原料。你需要自己分切、印刷，若自制套管还要先制筒，再去包膜。
- You have slitting / tube-making equipment in house自己有分切/制筒设备
- You print your own artwork or buy master rolls to re-sell自行印刷图案，或买母卷再分销
- You consume large volume and want the lowest per-kg cost用量大，追求最低公斤单价
2. Lay-flat sleeve: cut and shrink, no tube-making二、对折套管：裁切即套，无需制筒
A lay-flat sleeve is the same film folded into a hollow tube and delivered by folded flat width (roughly 20–600 mm). You cut a length, slide it over the pack, and apply heat — that is the whole process. It is the most popular finished product among overseas PACK buyers, especially small and mid-size assemblers without a tube-making machine.套管是把膜对折成中空扁筒，按扁折宽度供货（约 20–600mm）。你只需裁一段、套上电池组、加热收缩，工序就完成了。它是海外 PACK 客户采购最多的成品，尤其适合没有制筒机的中小组装厂。
- No tube-making equipment — only a cutter is needed没有制筒设备，只需裁切工具
- High size tolerance: strong transverse shrink grips minor pack tolerances尺寸容错高：横向收缩足，能包住轻微的电池组公差
- Blue is the standard lithium-battery look and is easy to QC on the line蓝色是锂电标准外观，产线质检一眼可辨
3. Insulation film: the high-safety grade三、绝缘膜：高安全等级
Insulation heat shrink film is a flame-retardant, optionally anti-static and anti-UV upgraded formula (thickness usually 0.10–0.20 mm, breakdown voltage around 8 kV and up). It is built for high-power energy-storage and power-battery modules where a short circuit carries real consequences. It can be supplied as flat film or as a sleeve.绝缘热缩膜是阻燃、可选抗静电与抗 UV 的升级配方（厚度通常 0.10–0.20mm，击穿电压约 8KV 起）。它为大功率储能与动力电池模组而生——这些场景一旦短路后果严重。平膜或套管两种形态都能做。
Rule of thumb: standard PVC film wins on cost, the sleeve wins on easy processing, and insulation film wins on safety. Pick for the risk profile of your pack, not just the price tag.一句话总结：普通 PVC 膜赢在成本，套管赢在好加工，绝缘膜赢在安全。按电池组的风险等级选型，而不是只看价格。
How to choose in 30 seconds30 秒选型法
- Power tools, consumer packs, cost-sensitive builds → flat film (if you process) or standard sleeve电动工具、消费电池、对成本敏感 → 能自己加工选平膜，否则选标准套管
- E-bike, outdoor packs with moisture exposure → standard or slightly upgraded film两轮车、户外潮湿环境 → 标准或轻度升级款膜
- Residential / C&I energy storage, forklift, AGV, export projects with strict safety specs → VW-1 flame-retardant, anti-static insulation film户用/工商业储能、叉车、AGV、安规严格的出口项目 → VW-1 阻燃、抗静电绝缘膜
Specifications you should tell the factory询价时要告诉工厂的参数
To get a usable quote in one round, send: cell model and pack dimensions (which determine sleeve flat width), thickness, color, shrink-process temperature (heat gun or tunnel), whether printing is needed (logo, polarity, voltage, warnings), estimated quantity, and your destination market (which decides RoHS, REACH, MSDS or UL/VW-1 paperwork).想一轮就拿到可用报价，请提供：电芯型号与电池组尺寸（决定套管扁折宽度）、厚度、颜色、收缩方式（热风枪还是热缩炉）、是否印刷（logo、极性、电压、警示标识）、预估数量和目标市场（决定 RoHS、REACH、MSDS 还是 UL/VW-1 文件）。
Next step下一步
Tell us your cell size, pack dimensions and artwork. We will confirm the right product form, thickness and certifications, and send a written quotation within one business day. Samples are free, freight collect.把电芯尺寸、电池组尺寸和印刷稿发给我们，我们会确认合适的形态、厚度与认证，并在 1 个工作日内出具书面报价。样品免费，运费到付。