CN109080468B

CN109080468B - Early warning method and system for battery module with overcharge protection device

Info

Publication number: CN109080468B
Application number: CN201810678668.XA
Authority: CN
Inventors: 孙国华; 郭月明; 曹勇; 郭其鑫; 王明强
Original assignee: China Aviation Lithium Battery Co Ltd; China Aviation Lithium Battery Research Institute Co Ltd
Current assignee: Avic Innovation Technology Research Institute Jiangsu Co ltd; China Aviation Lithium Battery Co Ltd; China Lithium Battery Technology Co Ltd; CALB Technology Co Ltd
Priority date: 2018-06-27
Filing date: 2018-06-27
Publication date: 2021-06-01
Anticipated expiration: 2038-06-27
Also published as: CN109080468A

Abstract

The invention relates to the field of power batteries of electric automobiles, in particular to an early warning method and system of a battery module with an overcharge protection device. The key points of the scheme are as follows: the battery monomer with the overcharge protection device forms a battery module through series-parallel connection, the overturning structure of the overcharge protection device in the battery monomer is connected with the positive plate and located below the negative plate, and when thermal runaway occurs, the overcharge protection device is triggered, and the battery is broken. The voltage acquisition line is fixed on the conductive bar and used for acquiring the voltage between two adjacent batteries of the parallel circuit and transmitting a voltage signal to the processor. The processor is used for receiving the voltage signal acquired by the voltage acquisition line and judging whether the current in the conductive bar is increased or not according to the voltage value, namely whether the current of the parallel loop is increased or not, so as to judge whether the thermal runaway of the single battery occurs or not and the internal short circuit of the battery is caused; and if the thermal runaway is generated, a command of stopping working is given to the battery module and an alarm signal is sent out.

Description

Early warning method and system for battery module with overcharge protection device

Technical Field

The invention relates to the field of power batteries of electric automobiles, in particular to an early warning method and system of a battery module with an overcharge protection device.

Background

The battery is the power source of electric automobile, and in order to satisfy different voltage and energy demands, automobile-used power lithium ion battery group uses by a certain number of battery cells through the mode of connecting in series and parallel in groups usually, promptly the battery module. At present, overcharge and thermal runaway protection of batteries are realized by installing an overcharge protection device on a lithium ion battery monomer with a ternary material as an anode, but after the batteries are grouped, due to the influence of production process and inconsistency of the single batteries, charge and discharge cannot be stopped when a battery module is in thermal runaway, and great threat is caused to the safety of the batteries and the whole vehicle. Therefore, it is very necessary to develop a safer battery module warning method and system.

Disclosure of Invention

The invention aims to provide an early warning method for a battery module with an overcharge protection device, which is used for solving the problem that charging and discharging cannot be stopped when the battery module is out of control due to heat.

In order to solve the technical problem, the invention provides an early warning method of a battery module with an overcharge protection device, which comprises the following steps:

1) collecting voltages between adjacent sampling points on the same conductive bar; the battery modules form a series connection and/or parallel connection structure by the conducting bars, and each sampling point corresponds to the positive electrode/negative electrode of one single battery;

2) and judging according to the voltage value, if the voltage value is increased, judging that the single battery is out of control thermally, and if the single battery is out of control thermally, sending an alarm signal by the processor.

The invention also provides an early warning system of the battery module with the overcharge protection device, so as to realize the following method:

The invention has the beneficial effects that:

the invention provides an early warning method and system for a battery module with an overcharge protection device, which are used for solving the problem of thermal runaway of the battery module consisting of batteries provided with the overcharge protection device due to overcharge, overheating, internal short circuit, collision, aging and the like. Adopt voltage acquisition line and treater to carry out real time monitoring to battery module, in time do stop work instruction and send out thermal runaway alarm signal when battery module thermal runaway, make technical staff or operating personnel can in time discover danger, guaranteed battery module's safety.

Furthermore, the voltage collecting wire is connected with the conducting bar in a welding mode.

Furthermore, the conducting bar is connected with the battery pole in a welding mode.

Further, the processor is a battery management system.

Drawings

FIG. 1 is a schematic diagram of the connection of a conductive bar to a voltage collection line;

fig. 2 is a flow chart of the early warning system of the battery module.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

For a lithium ion battery, an anode is a ternary material, a cathode is graphite, and an overcharge protection device is configured in the ternary material, and comprises a cathode turnover structure and an anode fusing structure, wherein the cathode turnover structure is positioned below a cathode of a single battery and is connected with the anode; and the over-flow of the anode fusing structure exceeds the rated current value, the anode fusing structure is fused, and the battery is disconnected.

The single lithium battery module with the overcharge protection device can be adapted to the early warning method of the present invention, which is described in detail below.

The 3P2S battery module formed by six single batteries (six single batteries are respectively (7, 1), (8, 2), (9, 3), (4, 10), (5, 11), (6, 12)) shown in fig. 1 is that the left three single batteries are connected in parallel, the right three single batteries are connected in parallel, and then the two groups of batteries connected in parallel are connected in series. The positive poles 7, 8 and 9 of the single batteries are connected through a first conducting bar, and the

negative poles

1, 2 and 3 are connected through a second conducting bar, so that three single batteries on the left side in the figure are connected in parallel; the

positive poles

4, 5 and 6 of the single batteries are connected through a third conductive bar, and the negative poles 10, 11 and 12 are connected through a fourth conductive bar, so that the three single batteries on the right side in the figure are connected in parallel, the

poles

3 and 4 are connected through a connecting conductor, and the two parallel battery packs are connected in series to form a series-parallel structure of the battery module. As shown in fig. 1, the voltage collecting line is connected to the processor, and its sampling point is welded to the conductive bar and connected to each battery post for measuring the potential at each position on the conductive bar. For example, the processor may obtain the voltage U1-2 between negative posts 1, 2 and the voltage U2-3 between

negative posts

2, 3 by detecting the sampling points. In general, in the same parallel loop, the potentials of the positive electrodes (or negative electrodes) of the two batteries are similar, and the voltage between U1-2 and U2-3 is extremely small. However, in the case of thermal runaway (overcharge, overheat, internal short circuit, collision, aging, etc.), due to internal short circuit of the battery, for example, short circuit of the batteries 8 and 2, U1-2 and U2-3 become large, so that the voltage change can be detected by the voltage collecting line and the processor sends out an alarm signal.

Thus, the process flow of the present invention is shown in FIG. 2: when thermal runaway (overcharge, overheating, internal short circuit, collision, aging and the like) occurs, the overcharge protection device is triggered, the batteries form short circuit, and the voltage acquisition line is used for acquiring the voltage between two adjacent batteries of the parallel circuit and transmitting a voltage signal to the processor. The processor is used for receiving the voltage signals acquired by the voltage acquisition lines and judging whether the current in the conductive bars is increased or not according to the increase of the voltage value or not, namely whether the current of the parallel battery modules is increased or not, so as to judge whether the thermal runaway of the single batteries occurs or not and the internal short circuit of the batteries is caused; and if the thermal runaway is generated, a command of stopping working is given to the battery module and a thermal runaway alarm signal is sent out.

The above method may be coded for execution in a processor. The processor may be a battery management system.

In addition, specifically, the conducting bar is connected with the lithium ion battery pole in a welding mode, the voltage collecting line is fixed above the conducting bar in a welding mode, and UV glue is coated at the welding point for protection.

Claims

1. The early warning method of the battery module with the overcharge protection device is characterized by comprising the following steps of:

1) collecting voltages between adjacent sampling points on the same conductive bar; the conducting bar forms the single batteries into a series connection structure, a parallel connection structure or a parallel connection structure; the anodes of the single batteries in the parallel structure are connected through the same conductive bar, and the cathodes of the single batteries are connected through the same conductive bar; each single battery is provided with an overcharge protection device for short-circuiting the single battery when the single battery is out of control due to heat; each sampling point corresponds to the anode/cathode of one single battery, and the collected voltage is the voltage between adjacent sampling points on the same conductive bar for realizing the parallel connection of the single batteries;

2) and judging according to the voltage value, if the voltage value is increased, judging that the current in the conductive bar is increased, judging that the single battery is out of control thermally, and if the single battery is out of control thermally, sending an alarm signal by the processor.

2. The early warning method for the battery module with the overcharge protection device according to claim 1, wherein the voltage collection line is welded to the conductive bar.

3. The early warning method of the battery module with the overcharge protection device according to claim 1 or 2, wherein the conductive bar is welded to the battery post.

4. The early warning method for the battery module with the overcharge protection device as recited in claim 1, wherein the processor is a battery management system.

5. The early warning system of the battery module with the overcharge protection device comprises a processor and a memory, and is characterized in that the processor executes instructions stored in the memory to realize the following method:

6. The early warning system of a battery module with an overcharge protection device of claim 5, wherein the processor is a battery management system.