CN106356939A - Method for detecting circuit opening of storage battery pack - Google Patents

Abstract

A method for detecting open circuit in a battery pack includes: acquiring the cell voltage of a preset number of cells in the battery pack and the open circuit voltage of each individual battery cell; calculating an average cell voltage based on the preset number of cells and their cell voltages; determining whether the average cell voltage is less than the open circuit voltage; if so, delaying for a preset time; after the preset delay, again determining whether the average cell voltage is less than the open circuit voltage; if so, then the batteries in the preset number of cells have an open circuit fault. This method for detecting open circuit in a battery pack has high detection efficiency and can quickly and promptly detect whether a section of batteries in the battery pack has an open circuit fault, thereby preventing and resolving safety hazards caused by open circuit problems in batteries.

Description

Battery pack open circuit detection method

technical field

The invention relates to the field of storage battery technology, in particular to a method for detecting an open circuit of a storage battery pack.

Background technique

When the battery or the connection of the battery or the internal reasons of the battery cause the battery to be disconnected for more than the set time, it is said that there is an open circuit. The reasons for the open circuit of the battery are:

(1) Contact problem: Because the screws of the connecting wire were not tightened during installation, the resistance of the connecting wire increases, and the battery will burn out the connecting wire after a long time, resulting in an open circuit.

(2) Environmental problems: The environment in which the battery is located causes the battery connecting strip to be corroded, which will cause an open circuit over time.

(3) Aging problem: The battery wiring has not been checked and maintained for a long time, and the connecting line is aging and disconnected.

(4) Battery damage: Because the battery is damaged, the entire battery pack cannot be connected together, resulting in an open circuit of the battery.

Therefore, once there is an open circuit in the battery, the battery pack will not be able to achieve the charging and discharging process. When the AC power supply of protection, communication, automation, emergency and other systems is disconnected, the battery pack as a backup power supply will not be able to provide the energy required for its operation, resulting in paralysis of various systems.

Contents of the invention

Based on this, it is necessary to provide a battery pack open-circuit detection method for the technical problem of how to improve detection efficiency.

A method for detecting an open circuit of a storage battery pack, comprising: obtaining the voltage of a preset number of cells in the battery pack and the open circuit voltage of a battery cell; calculating an average node voltage; judge whether the average node voltage is less than the open circuit voltage; if so, delay the preset time; after delaying the preset time, judge again whether the average node voltage is less than the open circuit voltage; if so, then There is an open-circuit fault in the batteries in the preset number of cells.

In one of the embodiments, the calculation of the average node voltage according to the preset number of nodes and the node voltage of the preset number of nodes includes: dividing the node voltage of the preset number of nodes by the preset number of nodes to obtain the average node voltage.

In one of the embodiments, the judging whether the average junction voltage is less than the open circuit voltage includes: subtracting the open circuit voltage from the average junction voltage to obtain a voltage difference; judging whether the voltage difference is less than zero, if yes, the average junction voltage is less than the open circuit voltage; if not, the average junction voltage is greater than or equal to the open circuit voltage.

In one of the embodiments, after delaying the preset time, judging whether the average cell voltage is lower than the open circuit voltage again includes: before delaying the preset time, setting the average cell voltage and the The open-circuit voltage is stored in the first storage address; after delaying the preset time, the voltage of the preset number of nodes in the storage battery pack and the open-circuit voltage of the battery cell are obtained; according to the preset number of nodes and the preset number of nodes Calculate the average node voltage; store the average energy saving and the open circuit voltage before the delay preset time to the second storage address; determine whether the average node voltage of the first storage address is is less than the open circuit voltage, and judging whether the average node voltage of the second storage address is less than the open circuit voltage.

In one of the embodiments, before the acquisition of the voltages of the preset number of cells in the battery pack and the open circuit voltage of the battery cells, it also includes: judging whether the float charge current of the battery pack is less than the preset current threshold; if so, Then preset the preset number of cells in the storage battery pack.

In one of the embodiments, the preset current threshold is 0.3 ampere.

In one of the embodiments, the acquisition of the voltages of the predetermined number of cells in the battery pack and the open circuit voltage of the battery cells includes: obtaining the total number of cells in the battery pack; dividing the total number of cells into the number of previous cells and The number of subsequent nodes, wherein the preset number of nodes is the number of preceding nodes or the number of subsequent nodes; respectively obtain the node voltage of the previous node number and the node voltage of the rear node number in the battery pack, and the voltage of the battery cell open circuit voltage.

In one of the embodiments, the calculation of the average node voltage based on the preset number of nodes and the node voltage of the preset number of nodes includes: respectively according to the node voltage of the previous number of nodes and the number of subsequent nodes Calculate the average node voltage of the preceding nodes and the average node voltage of the subsequent nodes.

In one of the embodiments, the judging whether the average node voltage is less than the open circuit voltage includes: respectively determining whether the average node voltage of the preceding node number is less than the open circuit voltage, and judging whether the average node voltage of the subsequent node number is lower than the open circuit voltage whether the average junction voltage is less than the open circuit voltage.

In one of the embodiments, after delaying for a preset time, when the average node voltage of the preceding nodes is lower than the open circuit voltage, and when the average node voltage of the subsequent nodes is lower than the open circuit voltage, the former There are open circuit faults in the number of storage battery packs and the storage battery packs in the latter number.

The above open-circuit detection method for a storage battery pack obtains the preset number of cell voltages in the battery pack and the open-circuit voltage of the battery cells, and calculates the average cell voltage based on the preset number of cells and the preset cell voltages. When the cell voltage is lower than the open circuit voltage, and the average cell voltage is still lower than the open circuit voltage after the preset time delay, it is determined that there is an open circuit fault in the battery with the preset number of cells. This method has high detection efficiency and can detect the battery pack in time. Whether there is an open-circuit fault in a certain section of the battery, thereby preventing and solving the potential safety hazard caused by the open-circuit problem of the battery.

Description of drawings

Fig. 1 is a schematic diagram of the application environment of the battery pack open circuit detection method in an embodiment;

Fig. 2 is a structural schematic diagram of a battery pack open circuit detection method in an embodiment;

Fig. 3 is a schematic flowchart of a method for detecting an open circuit of a battery pack in an embodiment.

detailed description

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described here, and those skilled in the art can make similar improvements without departing from the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

Please refer to FIG. 1 , which is a schematic diagram of an application environment of a battery pack open circuit detection method in an embodiment. The application environment includes a battery pack 110 , a processing terminal 120 , a charging and discharging machine 130 and a current transformer 140 . The battery pack 110 is composed of multiple battery cells. The charging and discharging machine 130 charges or discharges the battery pack 110 . The current transformer 140 measures the floating charge voltage of the charge-discharge machine 130 when the battery pack 110 is being charged or discharged. The processing terminal 120 obtains the cell voltage composed of the preset number of batteries and the open-circuit voltage of the battery cells through the wires, and calculates the average cell voltage according to the preset number of cells and the cell voltage of the preset number of cells. is less than the open circuit voltage, and when the average cell voltage is still less than the open circuit voltage after a preset time delay, it is determined that there is an open circuit fault in the batteries in the preset number of cells. In order to ensure that the battery is in the state of floating charge and detects that the battery has an open circuit state, in addition to monitoring the voltage of the battery group segment, at the same time use a high-precision current transformer combined with monitoring the floating charge current of the battery to open the circuit of the battery group detection.

In one embodiment, a method for detecting an open circuit of a battery pack is provided, and the specific implementation manner of this embodiment is described in detail with reference to the accompanying drawings, so that the purpose, features and advantages of this embodiment can be more clearly understood. As shown in FIG. 2 , it is a schematic diagram of the steps of a battery pack open circuit detection method 20 in an embodiment, and the battery pack open circuit detection method 20 includes:

Step S201: Obtain the cell voltages of a preset number of cells in the battery pack and the open circuit voltages of the battery cells.

Specifically: there are many reasons for the open circuit of the storage battery. If there is an open circuit in the storage battery, the charging and discharging process of the entire storage battery pack will not be possible. The battery pack is usually used as a backup power supply in protection, communication, automation, emergency and other systems. When the AC power supply of the protection, communication, automation, emergency and other systems is disconnected, the battery pack as a backup power supply will not be able to provide the required power supply for its operation. Therefore, it is necessary to regularly detect the open-circuit fault of a certain battery cell in the battery pack to prevent and solve the open-circuit problem of the battery.

For example, the acquisition of the voltages of the preset number of cells in the battery pack and the open circuit voltage of the battery cells includes: obtaining the total number of cells in the battery pack; dividing the total number of cells into the number of the previous cells and the number of the rear cells, wherein , the preset number of cells is the number of previous cells or the number of rear cells; the voltages of the first and last cells in the storage battery pack, and the open-circuit voltage of the battery cells are obtained respectively.

Referring to FIG. 1 , the battery pack 110 is composed of multiple battery cells. Connect two voltage lines U ₊ and U _- from both ends of the battery pack, and at the same time connect a tap U _to any node in the middle of the battery pack, so as to obtain the voltage of the preset number of cells in the battery pack, the The node voltage of the preset number of nodes is the voltage between the tap U _and the voltage line U ₊ or the voltage between the tap U _and the voltage line U ₋ . The open circuit voltage of the battery cell can be obtained from the parameters of the battery pack. For example, the total number of battery cells is X, and the number of battery cells in the front section is X1. Before the monitored voltage value U in U ₊ and U _{, after} the voltage value U in U _- and U _, the voltages of U ₊ and U _- are The voltage U of the storage battery pack and the open circuit voltage of the battery cell are U _open . Using U ₊ , U ₋ , U and U _open can determine whether there is an open circuit fault in the battery.

For example, before the acquisition of the voltages of the preset number of cells in the battery pack and the open circuit voltage of the battery cells, it also includes: judging whether the float charge current of the battery pack is less than the preset current threshold; if so, then preset the The preset number of cells in the battery pack. For example, the preset current threshold is set or modified according to actual conditions, for example, the preset current threshold is 0.1-0.5 ampere; for example, the preset current threshold is 0.3 ampere.

Step S202: Calculate an average node voltage according to the preset number of nodes and the node voltage of the preset number of nodes.

Specifically: After obtaining the cell voltage of the preset number of cells in the battery pack and the open circuit voltage of the battery cell, in order to judge the open circuit fault of a certain battery cell, the obtained cell voltage and the open circuit voltage of the battery cell should be Calculate and judge voltage, etc. For example, the average node voltage is obtained by dividing the node voltage of the preset number of nodes by the preset number of nodes.

For example, the calculation of the average node voltage according to the preset number of nodes and the node voltage of the preset number of nodes includes: calculating the average node voltage according to the node voltage of the preceding node number and the node voltage of the subsequent node number respectively The average node voltage of the number of nodes before and the average node voltage of the number of nodes after.

For example, the preset number of cells is the number of front-stage batteries or the number of rear-stage batteries, wherein the number of front-stage batteries plus the number of rear-stage batteries equals the total number of batteries. For example, record the average voltage of the front battery as U1, the average voltage of the rear battery as U2, the voltage of the front battery as U _front , and the rear battery voltage as U _rear , then according to the formula: U1=U _front /X1 and U2=U _rear / (X-X1) Calculate the average voltage value of the cells in the front and rear sections of the battery.

Step S203: Determine whether the average cell voltage is less than the open circuit voltage.

Specifically: For a battery pack or a battery cell that is working normally, the average voltage of any battery cell is roughly equal to the open circuit voltage of the battery cell. Therefore, when there is a large gap between the average cell voltage and the open circuit voltage , the possibility of an open circuit abnormality in the battery pack or battery cell will increase. This embodiment uses this principle to detect whether there is an open-circuit fault in the battery pack or a battery cell, so as to prevent and solve the open-circuit problem of the battery.

For example, the judging whether the average node voltage is less than the open-circuit voltage includes: respectively judging whether the average node voltage of the preceding nodes is less than the open-circuit voltage, and judging whether the average node voltage of the subsequent nodes is less than the open circuit voltage.

For example, the judging whether the average junction voltage is less than the open circuit voltage further includes: subtracting the open circuit voltage from the average junction voltage to obtain a voltage difference; judging whether the voltage difference is less than zero, if so, then The average junction voltage is less than the open circuit voltage; if not, the average junction voltage is greater than or equal to the open circuit voltage.

In the present embodiment, the average voltage of the storage battery in the front section is recorded as U1, the average voltage of the storage battery in the back section is U2, the voltage of the storage battery in the front section is _before U, and the voltage of the storage battery in the back section is _after U, then according to the formula: U1=U _before /X1 and U2= _Uhou /(X-X1) Calculate the average voltage value of the front and back sections of the battery, and then compare it with the _open circuit voltage U of the battery.

Step S204: If yes, delay for a preset time.

Specifically: the voltage measured by the voltage measuring device is fast and efficient, but the machine will work abnormally due to various factors. In order to reduce the abnormal detection factors caused by mechanical failures, avoid data errors caused by one-time measurement. Therefore, in this implementation, the voltage of the preset number of cells of the battery pack is detected twice through the method of secondary measurement and detection, and the second judgment is made. Therefore, after judging that the average cell voltage is less than the open circuit voltage, by delaying the preset time, the detection tool for detecting the cell voltage of the preset number of cells of the battery pack is measured again after a preset time delay, thereby reduce mistakes.

Step S205: After delaying for a preset time, judge again whether the average node voltage is less than the open circuit voltage.

Specifically: After judging that the average cell voltage is less than the open circuit voltage, by delaying the preset time, the detection tool for detecting the cell voltage of the preset number of cells of the storage battery pack is measured again after the delay of the preset time , repeat step S201 to step S203 at this time. For example, after delaying for a preset time, when the average voltage of the preceding cells is less than the open circuit voltage, and when the average voltage of the subsequent cells is lower than the open circuit voltage, the battery packs of the preceding and the storage battery packs with the number of the latter sections all have open-circuit faults.

For example, after delaying for a preset time, judging whether the average cell voltage is lower than the open circuit voltage again includes: before delaying for a preset time, storing the average cell voltage and the open circuit voltage to the first A storage address; after delaying the preset time, obtaining the voltage of the preset number of nodes in the storage battery pack and the open circuit voltage of the battery cell; according to the preset number of nodes and the voltage of the preset number of nodes, Calculating the average node voltage; storing the average energy saving and the open circuit voltage before the delay preset time in a second storage address; judging whether the average node voltage of the first storage address is less than the open circuit voltage , and judging whether the average node voltage of the second storage address is less than the open circuit voltage.

Step S206: If yes, then there is an open-circuit fault in the batteries in the preset number of cells.

Specifically: after delaying the preset time, record the average voltage of the front battery as U1, the average voltage of the rear battery as U2, the voltage of the _front battery as U, and the voltage of the rear battery as U _, and then according to the formula: U1=U _Front /X1 and U2=U _rear /(X-X1) Calculate the average voltage value of the front and rear cells of the battery, and then compare it with the _open circuit voltage U of the battery cell. If U1< _Uopen , it is judged that there is an open circuit fault in the rear battery, if U2< _Uopen , it is judged that there is an open circuit fault in the front battery, if both U1 and U2 are less than _Uopen , it is judged that both ends of the battery pack are open circuit, if If the values of U1 and U2 are close to 0, it is determined that there are open circuit faults in both the front and rear sections.

Please refer to FIG. 3 , which is a schematic flowchart of a battery pack open circuit detection method in an embodiment. With reference to FIGS. 2 and 3 , a specific detection process is used to describe the battery pack open circuit detection method.

First of all, by setting the total number of cells in the monitoring battery pack and the number of cells in the front section. For example, two voltage lines U ₊ and U _- are respectively connected from both ends of the battery pack, and at the same time, a tap U is connected to any section in the middle of the battery pack, the total number of batteries is X, and the number of batteries in the front section is X1.

Then, set the threshold value single open circuit voltage for judging the open circuit, and start real-time monitoring of the battery pack after completion. For example, remember that the detected voltage value of U ₊ and U _{is before} U, the voltage value of U- and U is _after U _, the voltage of U ₊ and U- is the battery pack voltage U, and the open circuit voltage of the battery cell is U _Open , use U ₊ , U _- , U and U _open to judge whether there is an open circuit fault in the battery.

Secondly, when the floating charge current is less than 0.3A, detect the size of the average voltage of the front section or the back section.

In addition, the average voltage is compared with the set open-circuit threshold voltage. If it is less than the open-circuit threshold voltage, a delay is performed. After the delay is completed, a comparison between the average voltage of the front section and the back section and the threshold value is performed. For example, record the average voltage of the front battery as U1, and the average voltage of the rear battery as U2, and then calculate the average value of the front and rear batteries according to the formula: U1=U _front /X1 and U2=U _rear /(X-X1) The voltage value is then compared with the open circuit voltage U of the battery cell.

Finally, the conclusion of the open-circuit fault in the battery pack is given. If U1< _Uopen , it is judged that there is an open circuit fault in the rear battery, if U2< _Uopen , it is judged that there is an open circuit fault in the front battery, if both U1 and U2 are less than _Uopen , it is judged that both ends of the battery pack are open circuit, if If the values of U1 and U2 are close to 0, it is determined that there are open circuit faults in both the front and rear sections.

Advantages of the present invention: by obtaining the preset number of node voltages in the storage battery pack and the open circuit voltage of the battery cells, and according to the preset number of nodes and the preset number of node voltages, the average node voltage is calculated. is less than the open-circuit voltage, and the average cell voltage is still lower than the open-circuit voltage after the preset time delay, it is determined that there is an open-circuit fault in the battery with the preset number of cells. This method has high detection efficiency and can quickly and promptly detect Whether there is an open circuit fault in a certain section of the battery, thereby preventing and solving the potential safety hazard caused by the open circuit problem of the battery.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. a kind of accumulator battery open circuit detection method, comprising:

Obtain the economize on electricity pressure of default joint number in accumulator battery and the open-circuit voltage of single battery；

According to the economize on electricity pressure of described default joint number and described default joint number, calculate average economize on electricity pressure；

Judge whether described average economize on electricity pressure is less than described open-circuit voltage；

If so, then time delay Preset Time；

After time delay Preset Time, judge whether described average economize on electricity pressure is less than described open-circuit voltage again；

If so, then there is open fault in the accumulator in described default joint number.

2. accumulator battery open circuit detection method according to claim 1 it is characterised in that described according to described default joint number And the economize on electricity pressure of described default joint number, calculate average economize on electricity pressure, comprising:

By the economize on electricity pressure of described default joint number divided by described default joint number, obtain described average economize on electricity pressure.

3. accumulator battery open circuit detection method according to claim 1 is it is characterised in that the described average economize on electricity of described judgement Whether pressure is less than described open-circuit voltage, comprising:

Described average economize on electricity pressure is deducted described open-circuit voltage, obtains voltage difference；

Judge whether described voltage difference is less than zero,

If so, then described average economize on electricity pressure is less than described open-circuit voltage；

If it is not, then described average economize on electricity pressure is more than or equal to described open-circuit voltage.

4. accumulator battery open circuit detection method according to claim 1 it is characterised in that described in time delay Preset Time Afterwards, judge whether described average economize on electricity pressure is less than described open-circuit voltage again, comprising:

Before time delay Preset Time, described average economize on electricity and described open-circuit voltage are stored to the first storage address；

After time delay Preset Time, obtain the open circuit electricity of economize on electricity pressure and the single battery of the default joint number in accumulator battery Pressure；

According to the economize on electricity pressure of described default joint number and described default joint number, calculate average economize on electricity pressure；

Described average economize on electricity and the described open-circuit voltage before time delay Preset Time are stored to the second storage address；

Judge whether the described average economize on electricity pressure of described first storage address is less than described open-circuit voltage, and judge described second storage Whether the described average economize on electricity pressure depositing address is less than described open-circuit voltage.

5. accumulator battery open circuit detection method according to claim 1 is it is characterised in that obtain in accumulator battery described Default joint number economize on electricity pressure and single battery open-circuit voltage before, also include:

Judge whether the floating current of accumulator battery is less than predetermined current threshold；

If so, then pre-set the default joint number in described accumulator battery.

6. accumulator battery open circuit detection method according to claim 5 is it is characterised in that described predetermined current threshold is 0.3 ampere.

7. accumulator battery open circuit detection method according to claim 1 is it is characterised in that in described acquisition accumulator battery The economize on electricity pressure of default joint number and the open-circuit voltage of single battery, comprising:

Obtain total joint number of accumulator battery；

Described total joint number is divided into front joint number and rear joint number, wherein, described default joint number is described front joint number or described deutomerite Number；

Obtain the economize on electricity pressure of front joint number in accumulator battery and the economize on electricity pressure of rear joint number, and the open circuit electricity of single battery respectively Pressure.

8. accumulator battery open circuit detection method according to claim 7 it is characterised in that described according to described default joint number And the economize on electricity pressure of described default joint number, calculate average economize on electricity pressure, comprising:

Respectively according to the economize on electricity pressure of described front joint number and the economize on electricity pressure of described rear joint number, before calculating the average economize on electricity pressure of joint number and The average economize on electricity pressure of joint number afterwards.

9. accumulator battery open circuit detection method according to claim 8 is it is characterised in that the described average economize on electricity of described judgement Whether pressure is less than described open-circuit voltage, comprising:

Judge whether the average economize on electricity pressure of described front joint number is less than described open-circuit voltage respectively, and judge the flat of described rear joint number All whether economize on electricity pressure is less than described open-circuit voltage.

10. accumulator battery open circuit detection method according to claim 9 is it is characterised in that after time delay Preset Time, institute When the average economize on electricity pressure stating front joint number is less than described open-circuit voltage, the average economize on electricity pressure of described rear joint number is less than described open-circuit voltage When, all there is open fault in the accumulator battery of the accumulator battery of described front joint number and described rear joint number.