Summary of the invention
The objective of the invention is deficiency, provide a kind of and can simply monitor out in real time each single-unit accumulator capacity, be convenient to the battery capacity check method of the electric car matrix electric battery of battery detecting and replacing, maintenance to above-mentioned technology.
Technical scheme of the present invention is following:
A kind of battery capacity check method of electric car matrix electric battery; It is characterized in that: adopt series-parallel accumulator matrix electric battery; In the matrix electric battery, all use a same resistance to link to each other between the node of every joint accumulator; Form the balance resistance network, reaching the effect that matrix connects between each accumulator, and utilize this resistance that each accumulator is reached equilibrium activity; The current signal of every row battery pack series connection in the sampling balance resistance network, other each the row nodes in every row of sampling are with respect to the first row voltages at nodes signal; Through computing obtain flowing through all size of current and the direction of each batteries; Obtain the electric quantity conditions of all batteries in the matrixing network through integration; Through the electric quantity data analysis of battery in charging or the discharge process accumulator balance resistance network, obtain each inducing capacity fading table of battery in the balance resistance network, thereby detect the battery capacity decline situation in the matrix of judging; Replace the fast battery of battery capacity decline in the matrix, can improve the battery capacity of matrix battery pack, reduce the replacement cost of accumulator.
The present invention is because the balance resistance network can also effectively promote freely moving of electric weight between the battery; The battery that guaranteed capacity is high can farthest be released the electric weight of self; The low battery of capacity also can effectively be protected in the matrix battery network simultaneously, has evaded in the series battery because the single-unit backwardness causes the phenomenon of whole Battery pack performance rapid deterioration.And then farthest bring into play the maximum economic benefit of matrix battery network.
The present invention detects the current value of the series connection battery pack of each row at current sensor of negative pole series connection of each row battery.
The present invention is to its magnitude of voltage of node measurement of each accumulator of the row of first in the matrix electric battery; Utilize magnitude of voltage and the current value of Ge Lie of the node of each each accumulator of row, calculate the current value that each joint accumulator flows through, and obtain the capacity of each accumulator, through data sampling, A/D conversion, data processing calculating and decision making.
The present invention has designed the data acquisition of a kind of accumulator cell charging and discharging of single-unit cheaply, calculating and management method; Can realize the real-time detection of single battery capacity; The operation conditions of group matrix accumulator and single accumulator is put in order in monitoring, can promptly and accurately determine the bad accumulator in the matrix electric battery, and changes in good time and should save accumulator; To guarantee the consistance of each batteries of matrix battery pack; Realize effectively electric charge resettlement between accumulator, prolong accumulator serviceable life, reduce the electric motor car use cost.The present invention can be applicable to fields such as electric automobile and mixed power electric car.
Embodiment
As shown in Figure 1, The present invention be directed to that m is capable, carry out the resistor network connection between the node of each accumulator of matrix electric battery of n row, all use a resistance R between each accumulator node
0Connect.For the principle of work of explaining the detection of matrix electric battery is done following explanation earlier:
(1) battery position numbering: the 1st sequence number that numeral is expert at for this battery, the 2nd numeral are the row that are listed as of battery place number.What for example ij represented is that i is capable, the battery of j row.Get a node at the positive pole place of each batteries, node number is this battery sequence number.
(2) electric current positive dirction regulation: for ij piece battery, for electric current on the column direction, downwards for just, promptly battery is emitted electric current for just.For the column direction electric current, be positive dirction to flow into the present node direction of current.
(3) current sample: above the first row battery,, obtain the size of current that flows into each row battery in first row, also be battery 11,21,31 through n current sampling resistor ..., the discharge current I of n1
1, I
2, I
3..., I
n
(4) connect a resistance balance network between cell row and the row, make that any two internodal resistance are equal in n the node with delegation, make that this resistance is R.The electromotive force at node i j place is φ
Ij
Like Fig. 2, appoint the node i j that gets the capable j row of i place to analyze, the electromotive force of this point is φ
Ij
At t constantly, can get formula 1 to ij point place utilization Kirchhoff's current law (KCL):
I ∈ (1, m) j ∈ (1, n) (formula 1)
As can be seen from
equation 1
by
launch.The electric current that earlier can obtain flowing out n battery on first row through the current sampling resistor on matrix first row is seen formula 2.Now the sampling network on capable through i can record the voltage U between i1 node and the arbitrary node ij
Ji1Because resistance R is known, can obtain any two node U
IsAnd U
IjBetween voltage see
formula 3.
I
J1=I
jJ ∈ (1, n) (formula 2)
(formula 3)
Can obtain any time arbitrary node place cell instantaneous discharge current by
formula 1, formula 2,
formula 3
To t
0Electric current in the-t time period carries out integration can obtain battery ij discharge electricity amount Q in this time period
Ij, see formula 4.
(formula 4)
Be carved into t during from t0 constantly by battery, battery ij discharge electricity amount Q
IjConstitute the electric weight matrix and see formula 5.
(formula 5)
Patrol and examine the electric weight Q of each point joint place in the electric weight matrix
Ij, and calculate current electric quantity matrix mean value E (Q (t
0, t)), extrapolate Δ Q
Ij(t
0, t)=Q
Ij-E (Q (t
0, t)).
(formula 6)
The present invention establishes a battery protecting circuit, and through a battery capacity safety of measuring constant, if when the inducing capacity fading data of battery are lower than this safe constant in the balance resistance network, battery protecting circuit provides alerting signal to the user.
If through safe constant p of measuring, p is a safety coefficient less than
.Under perfect condition, the electric weight criterion t of matrix battery is 0.The maximal value of the t consistance of baby battery more is just good more.
T=Δ Q
Ij(t
0, t)/E (Q (t
0, t))≤p (warning)
>p (safety) (formula 7)
With the accumulator is 12V12AH, and forming 4*4 accumulator matrix group is that embodiment (as shown in Figure 3) does a description to embodiment: through the balance resistance network, the equivalent resistance between each node is R, and is constantly as shown in table 1 to the circuit analysis of each node at t:
Node number |
Inflow current |
Flow out electric current |
11 |
I
11+(U
211+U
311+U
411)/R
|
I
21=I
11+(U
211+U
311+U
411)/R
|
21 |
I
21+(U
121+U
321+U
421)/R
|
I
31=I
21+(U
121+U
321+U
421)/R
|
31 |
I
31+(U
231+U
331+U
431)/R
|
I
41=I
31+(U
231+U
331+U
431)/R
|
41 |
I
41 |
|
12 |
I
12+(U
112+U
312+U
412)/R
|
I
22=I
12+(U
112+U
312+U
412)/R
|
22 |
I
22+(U
122+U
322+U
422)/R
|
I
32=I
22+(U
122+U
322+U
422)/R
|
32 |
I
32+(U
132+U
332+U
432)/R
|
I
42=I
32+(U
132+U
332+U
432)/R
|
42 |
I
42 |
|
13 |
I
13+(U
113+U
213+U
413)/R
|
I
23=I
13+(U
113+U
213+U
413)/R
|
23 |
I
23+(U
123+U
223+U
423)/R
|
I
33=I
21+(U
123+U
223+U
423)/R
|
33 |
I
33+(U
133+U
233+U
433)/R
|
I
43=I
31+(U
133+U
233+U
433)/R
|
43 |
I
43 |
|
14 |
I
14+(U
114+U
214+U
314)/R
|
I
21=I
14+(U
114+U
214+U
314)/R
|
24 |
I
24+(U
124+U
224+U
324)/R
|
I
31=I
24+(U
124+U
224+U
324)/R
|
34 |
I
34+(U
134+U
234+U
334)/R
|
I
41=I
34+(U
134+U
234+U
334)/R
|
44 |
I
44 |
|
Table 1
From t
0In time period constantly, the electric weight that flows out each batteries is as shown in table 2 to t:
Table 2
Through to the resolving of balance resistance network, can obtain single battery in the matrix electric battery t0 to t constantly battery capacity change.Through Δ Q
Ij(t
0, t)=Q
Ij-E (Q (t
0, t)) and calculate in the battery network single battery inducing capacity fading criterion matrix t suc as formula shown in 8 with reference to formula 7:
Formula 8
Suppose the situation that significantly fails to have occurred the angry t of the battery capacity criterion that to locate so at the battery at the 2nd row the 3rd row place
23<p.If when the continuous appearance of this decline criterion was lower than p 3 times, battery protecting circuit will provide alerting signal to the user.
The user can in time use special-purpose detecting instrument that this group matrix battery is detected to the matrix battery maintenance store of specialty after seeing matrix battery alarm signal, finds out the battery of inducing capacity fading and changes it.