CN109143096B - Device and method for detecting battery parameters of electric bicycle - Google Patents

Abstract

The invention discloses a battery parameter detection device of an electric bicycle, which belongs to the technical field of electric bicycles and comprises a microcontroller, and a voltage acquisition module, a current acquisition module, a memory and a liquid crystal display module which are connected with the microcontroller. The invention also provides a detection method of the battery parameters of the electric bicycle based on the detection device. The invention has the beneficial effects that: the state of the current battery can be accurately detected, a basis is provided for formulating a matched charging strategy for charging the battery, the cycle life of the battery can be effectively prolonged, and overcharging is prevented.

Description

Device and method for detecting battery parameters of electric bicycle

Technical Field

The invention belongs to the technical field of electric bicycles, and particularly relates to a battery parameter detection device and a battery parameter detection method for an electric bicycle.

Background

As the battery of the electric bicycle is aged, the internal resistance is increased, the capacity is reduced, the charging tail current is increased and the like in the use process, the situation that the battery cannot be timely converted from a uniform charging state to a floating charging state when the battery is charged by a charger can be caused, the service life of the battery is seriously shortened, and even a fire disaster is caused.

If the current state of the battery is detected in the charging starting process to formulate a corresponding charging method, the service life can be effectively prolonged, and the possibility of causing fire is reduced.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a device and a method for detecting battery parameters of an electric bicycle, which can detect the state of a battery of the electric bicycle before charging or in the process of starting charging, provide a corresponding charging strategy for charging the battery, prolong the service life of the battery and prevent overcharging.

In order to solve the technical problems, the invention adopts the technical scheme that: the battery parameter detection device for the electric bicycle is characterized by comprising a microcontroller, a voltage acquisition module, a current acquisition module, a memory, a liquid crystal display module and a battery temperature acquisition module, wherein the voltage acquisition module, the current acquisition module, the memory, the liquid crystal display module and the battery temperature acquisition module are connected with the microcontroller.

The invention also provides a detection method of the battery parameters of the electric bicycle, which is based on the detection device and comprises the following steps:

the method comprises the following steps of (1) establishing a battery parameter database and a relation curve database, wherein battery parameters in the battery parameter database comprise rated voltage, battery capacity, state of charge (SOC), maximum charging voltage and maximum charging current, and the relation curve database comprises corresponding relation curves of the battery voltage, the maximum charging voltage and the maximum charging current and the battery SOC, which are generated at a specific temperature according to batteries with different rated voltages and different capacities according to data in the battery parameter database;

step (2) establishing a typical battery model function

Wherein U is actually measured battery voltage, the range is 0-80V, U is rated battery voltage, the voltage comprises four voltages of 24V, 36V, 48V and 60V, SOC is the current battery charge state, the range is 0-100%, T is battery cathode temperature, i is actually measured charging current, the range is 0-10A, tau is set charging duration, C is battery capacity, and the range is 10 Ah-38 Ah;

step (3), detecting the actually measured battery voltage u and the battery cathode temperature T and comparing the actually measured battery voltage u and the battery cathode temperature T with data in a battery parameter database to obtain a group of possible solutions { u } of the primary battery parameters₀,T₀,U₁,SOC₁,C₁}，{u₀,T₀,U₂,SOC₂,C₂}，……，{u₀,T₀,U_n,SOC_n,C_n}；

Step (4), charging is carried out by current i, charging is stopped after charging time tau, and battery voltage u at the charging stopping time is detected₁And battery negative temperature T₁Calculating the SOC variation value Δ SOC to obtain a set of possible solutions:

{u₁,T₁,U₁,SOC₁+ΔSOC₁,C₁}，{u₁,T₁,U₂,SOC₂+ΔSOC₂,C₂}，……，{u₁,T₁,U_n,SOC_n+ΔSOC_n,C_n}，

wherein u is₁Satisfy the requirement of

Repeating the step (4) for N times to obtain N groups of battery parameter solution sets

Step (6), calculating the residual square sum of the actually measured voltage value and the calculated value of the parameter model

Then solving the solution with the minimum sum of squared residuals and SSR in the n groups of solution sets to obtain the solution with the best fitting degree with the curve of the typical battery model { U, SOC, C },

wherein the cell voltage is measured u_M，M＝1～N，

Predicted value u 'of battery model'_M＝f_m(U_m,SOC_m+M*ΔSOC_m,T_m)，M＝1～N,m＝1～n。

The invention has the beneficial effects that: the state of the current battery can be accurately detected, a basis is provided for formulating a matched charging strategy for charging the battery, the cycle life of the battery can be effectively prolonged, and overcharging is prevented.

The present invention will be described in detail with reference to the accompanying drawings.

Drawings

FIG. 1 is a schematic diagram of an electric bicycle battery parameter detection device in accordance with the present invention;

FIG. 2 is a graph of state of charge versus voltage.

In the drawings: the device comprises a microcontroller 1, a voltage acquisition module 2, a current acquisition module 3, a memory 4, a liquid crystal display module 5 and a battery temperature acquisition module 6.

Detailed Description

Referring to the attached drawing 1, the invention provides a battery parameter detection device for an electric bicycle, which comprises a microcontroller 1, and a voltage acquisition module 2, a current acquisition module 3, a memory 4, a liquid crystal display module 5 and a battery temperature acquisition module 6 which are connected with the microcontroller 1. The voltage acquisition module 2 and the current acquisition module 3 are used for acquiring voltage and current parameters when the battery is charged. The memory 4 is used for storing data such as programs and databases. The liquid crystal display module 5 is used for displaying the currently detected parameters. The battery temperature acquisition module 6 is used for acquiring the temperature of the negative electrode of the battery during charging.

In the above detecting device, the present invention provides a method for detecting parameters of a battery of an electric bicycle, which comprises the following steps:

and (1) establishing a battery parameter database and a relation curve database. The battery parameters in the battery parameter database comprise rated voltage, rated capacity, state of charge (SOC), maximum charging voltage and maximum charging current. The relation curve library comprises corresponding relation curves of battery voltage, maximum charging voltage and maximum charging current generated at a specific temperature according to batteries with different rated voltages and different capacities according to data in the battery parameter database (figure 2).

Step (2) establishing a typical battery model function

Wherein U is an actually measured battery voltage within a range of 0-80V, U is a rated battery voltage including four voltages of 24V, 36V, 48V and 60V, SOC is a current battery charge state within a range of 0-100%, T is a battery cathode temperature, i is an actually measured charging current within a range of 0-10A, tau is a set charging duration, C is a battery capacity, and a range of 10 Ah-38 Ah.

Step (3), detecting the actually measured battery voltage u and the battery cathode temperature T and comparing the actually measured battery voltage u and the battery cathode temperature T with data in a battery parameter database to obtain a group of possible solutions { u } of the primary battery parameters₀,T₀,U₁,SOC₁,C₁}，{u₀,T₀,U₂,SOC₂,C₂}，……，{u₀,T₀,U_n,SOC_n,C_n}。

Step (4), charging is carried out by current i, charging is stopped after charging time tau, and battery voltage u at the charging stopping time is detected₁And battery negative temperature T₁Calculating the SOC variation value Δ SOC to obtain a set of possible solutions:

{u₁,T₁,U₁,SOC₁+ΔSOC₁,C₁}，{u₁,T₁,U₂,SOC₂+ΔSOC₂,C₂}，……，{u₁,T₁,U_n,SOC_n+ΔSOC_n,C_nin which u₁Satisfy the requirement of

Repeating the step (4) for N times to obtain N groups of battery parameter solution sets

Step (6), calculating the residual square sum of the actually measured voltage value and the calculated value of the parameter model

Wherein the cell voltage is measured u_M，M＝1～N，

Predicted value u 'of battery model'_M＝f_m(U_m,SOC_m+M*ΔSOC_m,T_m)，M＝1～N,m＝1～n，

And then solving the solution with the minimum sum of squares of residual errors in the n groups of solutions and SSR to obtain the solution { U, SOC, C } with the optimal fitting degree with the typical battery model curve, and obtaining the parameters (the rated battery voltage value, the current battery state of charge value and the battery capacity) of the current battery.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention and not to limit it; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that: modifications to the specific embodiments of the invention or equivalent substitutions for parts of the technical features may be made; without departing from the spirit of the present invention, it is intended to cover all aspects of the invention as defined by the appended claims.

Claims (1)

1. A method for detecting parameters of a battery of an electric bicycle is characterized by comprising the following steps:

the method comprises the following steps of (1) establishing a battery parameter database and a relation curve database, wherein battery parameters in the battery parameter database comprise rated voltage, battery capacity, state of charge, maximum charging voltage and maximum charging current, and the relation curve database comprises a corresponding relation curve of battery voltage and battery SOC generated at a specific temperature according to different rated voltages and batteries with different capacities according to data in the battery parameter database;

step (2) establishing a typical battery model function

Wherein U is actually measured battery voltage, the range is 0-80V, U is rated battery voltage, the voltage comprises four voltages of 24V, 36V, 48V and 60V, SOC is the current battery charge state, the range is 0-100%, T is battery cathode temperature, i is actually measured charging current, the range is 0-10A, tau is set charging duration, C is battery capacity, and the range is 10 Ah-38 Ah;

step (3), detecting the actually measured battery voltage u and the battery cathode temperature T and comparing the actually measured battery voltage u and the battery cathode temperature T with data in a battery parameter database to obtain a group of possible solutions { u } of the primary battery parameters₀,T₀,U₁,SOC₁,C₁}，{u₀,T₀,U₂,SOC₂,C₂}，……，{u₀,T₀,U_n,SOC_n,C_n}；

Step (4), charging is carried out by current i, charging is stopped after charging time tau, and battery voltage u at the charging stopping time is detected₁And battery negative temperature T₁Calculating the SOC variation value Δ SOC to obtain a set of possible solutions:

{u₁,T₁,U₁,SOC₁+ΔSOC₁,C₁}，{u₁,T₁,U₂,SOC₂+ΔSOC₂,C₂}，……，{u₁,T₁,U_n,SOC_n+ΔSOC_n,C_n}，

wherein u is₁Satisfy the requirement of

Repeating the step (4) for N times to obtain N groups of battery parameter solution sets

Step (6), calculating the residual square sum of the actually measured voltage value and the calculated value of the parameter model

Then solving the solution with the minimum sum of squared residuals and SSR in the n groups of solution sets to obtain the solution with the best fitting degree with the curve of the typical battery model { U, SOC, C },

wherein the cell voltage is measured u_M，M＝1～N，

Predicted value u 'of battery model'_M＝f_m(U_m,SOC_m+M*ΔSOC_m,T_m)，M＝1～N，m＝1～n。

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