|
| DSH 384: s- g# q' A# C* ~8 s8 Z
8 E( T% P5 A+ [ | Lithium Cell Protection2 B- a( c( _( l N+ r
| 4.3.21
6 C: _5 `8 m6 P5 M: l | 60950(ed.2)5 I! ^1 H! K+ ~: z5 D4 p# s# ?% ?
|
, M* Q2 f. X' b! ^. P: M8 sStandard: IEC60950, 2nd Clause: 4.3.21 Sheet n. P384
" O3 a2 W9 r" B6 T' i8 mPage 1(1)+ j4 {* ]+ K/ @/ y3 N. ~! r
Subject: Lithium Cell Protection Key words:
. ]3 E# z* M6 j5 s-Lithium Cell& Z# l0 I$ G7 z* q- q5 Q
-Clearances
! L# i( X9 i& \0 w/ [. L2 U- failure mode
* C$ h- O" W; d: l( D* K, EProvisional Decision taken by ETF23 F1 l, J4 a1 @5 _, M
and to be approved by CTL at its
2 ^/ X% n% @) ]! H) S( {" ?38th meeting, in Toronto
; t- l# | g. u; q& s) D0 ^Question:' c! \: I; j3 o, M" I
Clause 4.3.21 requires that two levels of protection are required to prevent forced or reversed charge
/ M$ L2 S1 [- {5 R [) \: T5 qor forced discharge if this would result in a hazard. Conventionally a combination of resistor, diode
/ r: K5 k% b$ Cor ic has been considered suitable and is for the series current path. However, a new consideration* @" E+ j7 O0 X
has been raised in respect of adjacent tracks, separated by no more than operational insulation, which,
1 f# J+ m& J; w) Hunder s/c conditions will bypass the protective series components and provide charging current for+ b1 N* R+ D) ]
either chargeable or non-rechargeable batteries. Does this mean that there is therefore a requirement6 t9 n( `- ?" k* _$ d" N
for Reinforced separation? ]- y2 d$ `3 _% ^
If that is the case, then the controlling factor is the clearance of 0.8mm in Table 5 (circuits not subject
/ X4 p; p9 L3 L! g! u6 Pto transient over voltage). This is based on the fact that creepage cannot be less than clearance and
7 ^- R" ?, I7 o" E6 N1 @creepage can be calculated to be, for example at +5V, 0.4mm (based on rounding up 0.12mm to
( B' ~- q. D$ l4 U0.2mm for Basic and doubling for reinforced.
7 K1 H7 l) ]/ P! ?; _4 mDecision:9 D7 p; z# g" `& ?3 `/ q
Operational insulation is suitable taking into account 5.4.4 because there is no risk of electric shock.
7 F0 {* e, N X {8 ?# V* G(see 1.2.9.1)
( v" i' c/ P+ j: P. lCare should be taken by determining clearance and creepage distances which column of the table has& n3 A/ q2 g+ l/ v3 y. V, e
to be used.(Transients have to be taken into account)
: I" x. x V# |; D+ x& q7 H1 N0 y; s5 g% p
( t5 z1 F# ?9 ^8 V& t
|
本帖子中包含更多资源
您需要 登录 才可以下载或查看,没有帐号?注册安规
x
|