Dɛn ne nkwammoaa a ɛkari pɛ a wɔde di dwuma wɔ lithium batere mu?

Nov 26, 2025

Gyae nkrasɛm bi .

Ɛkame ayɛ sɛ mayɛ battery pack teardown ne BMS design mfe 12 ni. Bere biara a obi bebisa me sɛ "dɛn ankasa na balancing yɛ?", mekyerɛ wɔn mfonini abien kɛkɛ: biako yɛ 2-mfe-old 36 V e-bike pack a enni balancing (nkwaboaa no fã wɔ 1.8 V, nkae no wɔ 4.18 V), foforo no yɛ batch koro no ara a ɛwɔ 100 mA passive balancer (nkwaboaa nyinaa da so ara wɔ 12 mV mu wɔ mfe abiɛsa akyi). Ɛno ne asɛm a ɛwɔ mfonini biako mu nyinaa.

Wɔ akuw ankasa mu no, wɔwo nkwammoaa sɛ wɔyɛ pɛ da. Fa Samsung 50E nkwammoaa foforo 100 fi tray koro no ara mu: tumi a ɛtrɛw taa yɛ ±30 mAh, self-discharge rate betumi ayɛ soronko mpɛn 2–3, na emu resistance betumi ayɛ soronko 3–5 mΩ. Wɔ kyinhyia 200 akyi no, wɔn a wɔyɛ mmerɛw no di akyi kɛse mpo. Sɛ wɔankari pɛ a, nkwammoaa a ɛyɛ mmerɛw sen biara a ɛwɔ charge ne nkwammoaa a ɛyɛ den sen biara a ɛwɔ discharge no na ɛkyerɛ pack tumi. Wohwere 20–40 % a wotumi de di dwuma wɔ afe a edi kan no nkutoo mu.

Active Cell Balancing

Akwan abien pɛ na nkurɔfo fa so kari pɛ ankasa wɔ nneɛma a wɔyɛ mu:

Eyi ne nea packs a ennu 20 kWh 95 % de di dwuma.
Chips ankasa a wubehu wɔ board ahorow so:

TI BQ769x2 / BQ769x3 / BQ78z100 na ɛwɔ hɔ a

Analog Mfiri LTC6804 / LTC6811 / LTC6813

Maxim MAX14920 / MAX14921 a ɛyɛ kɛse

NXP MC33771 / MC33772 na ɛwɔ hɔ

Mogya a ɛtaa ba: 80–150 mA (BQ76952 betumi apia 220 mA sɛ wode pin abien di nsɛ a).
Resistor boɔ wɔ mass production mu: ɛkame ayɛ sɛ bere nyinaa 27 Ω anaa 33 Ω 2512 1 W package.
Trigger nhyehyɛe a mede di dwuma ankasa:
Fi ase mogya tu wɔ 15–25 mV a ɛboro pack average so wɔ CV bere mu, gyae bere a delta kɔ fam sen 6–8 mV.
Sɛ wobɔ mmɔden sɛ wobɛtaa 2 mV a wobɛnoa board no ara kwa daa.

Ɔhyew ne ɔhaw no ankasa. 16s skuter pack a mogya 100 mA wom betumi atow 7–8 W agu BMS PCB no so tẽẽ. Ɛno nti na saa e-bike boards a ne bo yɛ mmerɛw a ne bo yɛ dɔla 20-da no twitwiw na ɛpaapae wɔ awɔw bere biako akyi wɔ owia mu.

Sɛ wokɔ soro ~30 kWh pɛ a ɛkame ayɛ sɛ obiara dan kɔ active so.

Real-wiase nhwɛso ahorow a mabubu agu:

Tesla Model S/X (2012–2021): DC-DC birikisi nketewa wɔ HVJB no so, ~1 A wɔ module biara mu

BMW i3 (mfe nyinaa): inductive transformer module, 24-to-1 ratio, bɛyɛ 2 A

BYD Blade packs: wimhyɛn-capacitor boards a egyina Infineon TLF35568 nkyerɛkyerɛmu nhyehyɛe so

Chinafo a wɔkora nneɛma so a ɛyɛ den: DC-DC module ahorow a wɔatew wɔn ho a ɛkɔ 15–20 A wɔ 700 V ahama no nyinaa so

Off-the-shelf boards nkurɔfo tɔ ankasa:

1–2 AliExpress a ɛyɛ ahabammono a ɛtu-capacitor boards (wɔn a ɛwɔ relay nketewa 8–16) .

Heltec / Orion BMS Gen4 / REC Q / Dilithium: 5–8 A a ɛwɔ onwini a ɛfata

Cell Balancing

OEM dodow no ara kari pɛ wɔ SoC 10–15 % a ɛwɔ soro no nkutoo mu efisɛ voltage curve no yɛ petee dodo wɔ 3.45 V (NMC) anaa 3.40 V (LFP) ase.
Tesla waits until >90 % SoC na nko ara tu mmirika kari pɛ ma 30–60 min a etwa to a wɔbɔ ka.
Me 2017 BMW i3 logs kyerɛ sɛ inductive balancer no nyane nkutoo bere a delta > 30 mV na pack current < 5 A.

Mewɔ drawer a 2016–2018 low-speed EV packs a efi China asasepɔn so a ɛkoraa $0.80 denam mogya a ɛko tia no a wɔpopae no ahyɛ mu ma. Asram 18 akyi no nkwammoaa a ɛyɛ mmerɛw no kɔ negative biara a ɛbɛtow, kɔbere nwene, dendrites nyin, separator melts, ogya. Mahwɛ sɛ 72 V 20 Ah packs akɔ fam akodu 8–9 Ah a wobetumi de adi dwuma wɔ asram 14 mu. Slap a $12 active balancer wɔ wɔn so na wɔsan ba 18–19 Ah. Asuade a wosuae wɔ ɔkwan a ɛyɛ den so.

Under 15 kWh → passive yɛ papa na ɛbɛtena hɔ daa (skuter, anyinam ahoɔden nnwinnade, drones) .

400 V+ or >50 kWh → active anaasɛ wobɛsesa module afe biara

EV biara a ɛfata a wɔtɔn nnɛ no wɔ kari pɛ. Nsakraeɛ baako pɛ ne sɛ ɛyɛ 33 Ω resistor anaa $300 active board.

Ɛno ne nkwammoaa a ɛkari pɛ. Biribiara nni hɔ a ɛyɛ anwanwadeɛ. Nkwammoaa pa no a onua biako a ɔyɛ ɔkwasea a osii gyinae sɛ obenyin ntɛmntɛm no antwe wɔn akɔ fam no a wobesiw ano ara kwa.

Cell Balancing