CN210692723U

CN210692723U - Battery with self-heating and safety protection functions

Info

Publication number: CN210692723U
Application number: CN201921601137.7U
Authority: CN
Inventors: 张开
Original assignee: Faros Suzhou Energy Technology Co Ltd
Current assignee: Faros Suzhou Energy Technology Co Ltd
Priority date: 2019-09-25
Filing date: 2019-09-25
Publication date: 2020-06-05
Anticipated expiration: 2029-09-25

Abstract

A battery with self-heating and safety protection functions belongs to the technical field of new energy batteries. This battery that possesses self-heating and safety protection function includes: the battery comprises a battery shell made of high-resistance materials, a battery anode cover plate and a battery cathode cover plate; the battery anode cover plate and the battery cathode cover plate are respectively provided with a cover plate metal framework, a pole and a bimetallic strip; the cover plate metal framework is provided with a pole mounting hole, a pole is fixed in the pole mounting hole, and the pole is connected with the bimetallic strip; the cover plate metal framework is packaged in the insulating part and insulated from the pole; the insulating part is provided with a groove corresponding to the bimetallic strip, and the metal framework of the cover plate at the groove is exposed; one end of the bimetallic strip is packaged in the insulating part and is in contact with the exposed cover plate metal framework when in a deformation state, and an external circuit is formed by conduction. The utility model discloses can realize low temperature self-heating to can avoid the inside thermal runaway of battery to cause the risk of starting a fire, exploding.

Description

Battery with self-heating and safety protection functions

Technical Field

The utility model relates to a technique in new energy battery field specifically is a battery that possesses self-heating and safety protection function.

Background

Lithium ion batteries are widely used in the fields of mobile communication, notebook computers, electric bicycles, electric automobiles and the like due to their advantages of high energy density, light weight, long service life, low self-discharge rate, no memory effect and the like. Especially, with the development of modern society, environmental problems are more and more concerned by people, the new energy automobile industry is rapidly developed under the strong support of governments, the demand of power lithium ion batteries is gradually increased year by year, and correspondingly, more and more social capital and power battery production and research are involved by listed companies.

With the continuous release of new energy automobile market, electric vehicles in the whole country and around the world are in continuous emergence of accidents of fire and explosion, and the safety problem of lithium ion batteries is more and more concerned by battery manufacturers, consumers, government departments and other social circles. Safety issues become one of the obstacles that restrict the rapid spread of electric vehicles. Meanwhile, due to the characteristics of the lithium ion battery, the charge-discharge performance of the lithium ion battery is poor at low temperature, particularly, lithium dendrites are easily formed in the battery during charging at low temperature, and the potential safety hazard of short circuit in the battery is caused by puncturing a diaphragm along with the continuous growth of the lithium dendrites. The method has certain influence on the popularization of new energy automobiles, especially in regions with low temperature in winter. Whether a battery has excellent low-temperature performance is a key to opening the market in these regions.

Aiming at the safety problem of the power battery, a better solution is not provided at a single battery end, although the explosion-proof valve is additionally arranged on the cover plate, the explosion risk of the battery can be reduced as much as possible, but an active defense mechanism is not provided. Aiming at the problem of low temperature, the method generally adopted by power battery enterprises at present is to introduce a heating system at the PACK end of a battery system and heat the battery at low temperature. The method not only increases the PACK cost of the battery, but also has lower heating efficiency and lower grouping efficiency of the system.

In order to solve the above problems existing in the prior art, the utility model discloses come from this.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the aforesaid that exists to prior art is not enough, provides a battery that possesses self-heating and safety protection function, can realize low temperature self-heating to can avoid the inside thermal runaway of battery to cause the risk of starting a fire, exploding.

The utility model relates to a battery that possesses self-heating and safety protection function, include: the battery comprises a battery shell made of high-resistance materials, a battery anode cover plate and a battery cathode cover plate;

the battery anode cover plate and the battery cathode cover plate are respectively provided with a cover plate metal framework, a pole and a bimetallic strip; the cover plate metal framework is provided with a pole mounting hole, and a pole is fixed in the pole mounting hole; the cover plate metal framework is packaged in the insulating part and insulated from the pole; the insulating part is provided with a groove corresponding to the bimetallic strip, and the metal framework of the cover plate at the groove is exposed; one end of the bimetallic strip is packaged in the insulating part and is in contact with the exposed cover plate metal framework when in a deformation state, and an external circuit is formed by conduction.

In some technical schemes, a high-resistance material connecting sheet is connected between the pole and the bimetallic strip; the function of the battery shell is the same as that of a battery shell made of a high-resistance material, and the battery shell limits the current when the self-heating function is started after an external circuit is conducted, so that the battery is prevented from being damaged due to overlarge current after the positive electrode and the negative electrode of the battery are in short circuit. The high-resistance material connecting sheet is packaged in the insulating piece and is insulated from the cover plate metal framework.

Preferably, the battery shell made of the high-resistance material is made of a metal simple substance, an alloy, a semiconductor and a conductive polymer material, the resistance is not less than 100m omega, and different resistance materials can be freely selected according to different capacities and internal resistances of the battery core.

Preferably, the high-resistance material connecting sheet is made of metal simple substances, alloys, semiconductors and conductive polymer materials, the resistance is not less than 100m omega, and different resistance materials can be freely selected according to the difference of the capacity and the internal resistance of the battery core and the internal resistance of the battery shell made of the high-resistance material.

The insulating part is formed by solidifying high-temperature-resistant insulating glue.

For the battery anode cover plate, a liquid injection hole is arranged on the metal framework of the cover plate, grooves are formed at two ends of the liquid injection hole by the insulating part, the liquid injection hole is sealed by a sealing rubber plug, and preferably, a sealing cap is arranged on the sealing rubber plug; this seal design can avoid battery internal pressure too high, and the bad apron metal framework in top causes the risk of electrolyte leakage, further promotes the security performance of battery.

A pole core is arranged in the high-resistance material battery shell, and an anode tab on the pole core is fixedly connected with an anode post on a battery anode cover plate and a cathode tab on the pole core is fixedly connected with a cathode post on a battery cathode cover plate through flexible connections respectively; preferably, the flexible connection is welded and connected with the pole through laser welding, and is welded and connected with the pole lug on the pole core through ultrasonic welding.

And the joints between the pole core and the battery anode cover plate and between the pole core and the battery cathode cover plate are respectively wrapped by high-temperature-resistant insulating glue.

Under the normal state, the bimetallic strip and the battery main body are in an open circuit state, and the battery can be charged and discharged normally; the bimetallic strip is turned over only under the set temperature condition, and the strict control of the turning temperature of the bimetallic strip can be realized by adopting different metal alloy materials; when the environmental temperature is lower than a certain temperature, such as-30 ℃, based on the self characteristics, the bimetallic strip automatically turns over to be in contact with the battery shell made of the high-resistance material, and is conducted to form an external conductive loop; when the battery is short-circuited or thermal runaway occurs inside the battery, the temperature rises rapidly to exceed a certain temperature, such as 90 ℃, and the battery can also be in contact conduction with the battery shell made of the high-resistance material through the turnover of the bimetallic strip, so that the energy inside the battery is released, and the fire and explosion caused by overhigh temperature and overhigh pressure inside the battery are avoided.

In addition, the battery shell made of high-resistance materials and the connecting sheet made of the high-resistance materials with different resistance values can be selected, and different heating rates of the battery shell and the connecting sheet are realized when an external circuit is conducted; when the battery is heated to a certain temperature or reaches a chargeable temperature, such as 5 ℃, the bimetallic strip turns over, and the heating loop is cut off, so that the battery loss is reduced.

Of course, the turning of the bimetal can also be actively controlled more flexibly by adding an external device, for example, an active response mechanism is introduced into a BMS (battery management system), and the turning of the bimetal can be realized by an external force and the external device. In addition, the battery pack can achieve the effect of active equalization of SOC (State of Charge) between the battery cells through the BMS and the external device.

Technical effects

Compared with the prior art, the utility model discloses following technological effect has:

1) the bimetallic strip on the battery cover plate is used as a thermal switch, and the bimetallic strip is turned over according to different thermal expansion and contraction tensions on two surfaces caused by temperature difference, so that the external circuit of the battery is closed or disconnected, low-temperature self-heating is realized, and the risk of fire and explosion of the battery is reduced;

2) after an external circuit is conducted at low temperature, the battery shell made of a high-resistance material is used as a heating sheet, auxiliary devices such as a heating film and the like are not required to be designed, the design space of the battery is greatly saved, and the production cost is reduced;

3) simple structure, low cost and easy industrialization.

Drawings

FIG. 1 is a schematic view of the entire structure of embodiment 1;

FIG. 2 is a schematic cross-sectional view of a positive electrode cap plate of the battery of embodiment 1;

FIG. 3 is a schematic view showing the inner side structure of the positive electrode cap plate of the battery of embodiment 1;

FIG. 4 is a schematic view showing the outer side structure of the positive electrode cap plate of the battery in example 1;

in the figure:

the battery comprises a battery positive electrode cover plate 1, a high-resistance material battery shell 2, a pole core 3, a positive electrode tab 4, a negative electrode tab 5 and a battery negative electrode cover plate 6;

the terminal post 11, the bimetallic strip 12, the sealing cap 13, the cover plate metal framework 14, the liquid injection hole 15, the sealing rubber plug 16, the insulating plastic part upper layer 17, the insulating plastic part lower layer 18 and the soft connection 19;

a connecting piece 110 made of high-resistance material and a laser welding spot 191.

Detailed Description

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

Example 1

As shown in fig. 1, the present embodiment relates to a square-shell lithium battery, the size of the battery is 173mm long, 27mm thick, 112mm high, and 50Ah capacity, and the positive electrode is made of lithium iron phosphate material. The shape of the battery is not limited to a square shape, and a cylindrical shape or the like may be used.

This square shell lithium cell includes high resistance material battery case 2, anodal apron 1 of battery and battery negative pole apron 6, is equipped with utmost point core 3 in the high resistance material battery case 2, and utmost point core 3 is connected with anodal apron 1 of battery through anodal utmost point ear 4, is connected with battery negative pole apron 6 through negative pole utmost point ear 5.

The battery cover plate structure is described by taking the battery positive electrode cover plate 1 shown in fig. 2 as an example, the main structure of the battery cover plate is a cover plate metal framework 14, and the battery cover plate is roughly in a three-layer frame structure by taking the cover plate metal framework 14 as a boundary; the cover plate metal framework 14 of the present embodiment is made of aluminum, but not limited thereto.

The cover plate metal framework 14 is provided with a pole mounting hole, a pole 11 is fixed in the pole mounting hole, and the cover plate metal framework 14 is coated on the insulating plastic part and insulated from the pole 11. The insulating plastic part upper layer 17 is internally coated with a high-resistance metal connecting sheet 110, one end of the high-resistance metal connecting sheet 110 is connected with the pole 11, and the other end of the high-resistance metal connecting sheet is connected with the bimetallic strip 12; corresponding to the bimetallic strip 12, the upper layer 17 of the insulating plastic part is provided with a groove, the cover plate metal framework 14 at the groove is exposed, one end of the bimetallic strip 12 is packaged in the upper layer 17 of the insulating plastic part and is in contact with the exposed cover plate metal framework 14 when in a deformation state, and an external circuit is formed by conduction.

The insulation plastic part lower layer 18 realizes the insulation of the cover plate metal framework 14 and the battery internal pole core 3, and the joint between the battery internal pole core 3 and the cover plate is wrapped by high-temperature-resistant insulating glue (not shown in the attached drawings). The pole 11 is fixed with a soft connection 19 on one side of the lower layer 18 of the insulating plastic part by laser welding, and 191 shown in fig. 3 is a laser welding spot 191 between the pole 11 and the soft connection 19; the flexible connection 19 is welded and connected with the upper electrode lug of the electrode core 3 in the battery by ultrasonic welding.

The structural difference between the battery positive electrode cover plate 1 and the battery negative electrode cover plate 6 is only that the battery positive electrode cover plate 1 is also provided with an explosion-proof structure, as shown in fig. 2 and 4. This explosion-proof construction is including setting up notes liquid hole 15 on apron metal framework 14, and insulating plastic part forms the recess at notes liquid hole 15 both ends, annotates liquid hole 15 and seals through sealing rubber buffer 16, is equipped with on the sealing rubber buffer 16 and seals block 13.

The resistance values of the battery case 2 made of the high-resistance material and the connecting sheet 110 made of the high-resistance material are both 600m omega; the bimetal strip 12 will automatically turn over when the temperature is low, such as-30 ℃ or high, such as 90 ℃, and the circuit outside the shell is connected. After the outer loop is switched on, the loop current is about 50A. When the temperature returns to the range of 0-60 ℃, the bimetallic strip returns to the original state, and the external loop is cut off.

In addition, the outer loop can be disconnected when the voltage inside the battery cell is lower than the lowest voltage allowing discharge. The process needs an external facility for assistance, and generally, when the SOC of the battery is ensured to be more than or equal to 20 percent, the intervention of the external facility is not needed.

In the embodiment of the invention, the pole core 3 adopts the current mainstream winding or lamination process, and the pole core 3 preferably adopts a mode of leading out lugs at two ends, but the invention is not limited to the mode; the positive electrode tab 4 and the negative electrode tab 5 can be formed by die cutting, laser cutting or additional ultrasonic welding.

It is to be emphasized that: the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form, and any simple modifications, equivalent changes and modifications made by the technical spirit of the present invention to the above embodiments are all within the scope of the technical solution of the present invention.

Claims

1. A battery with self-heating and safety protection functions is characterized by comprising: the battery comprises a battery shell made of high-resistance materials, a battery anode cover plate and a battery cathode cover plate;

the battery anode cover plate and the battery cathode cover plate are respectively provided with a cover plate metal framework, a pole and a bimetallic strip; the cover plate metal framework is provided with a pole mounting hole, a pole is fixed in the pole mounting hole, and the pole is connected with the bimetallic strip; the cover plate metal framework is packaged in the insulating part and insulated from the pole; the insulating part is provided with a groove corresponding to the bimetallic strip, and the metal framework of the cover plate at the groove is exposed; one end of the bimetallic strip is packaged in the insulating part and is in contact with the exposed cover plate metal framework when in a deformation state, and an external circuit is formed by conduction.

2. The battery with self-heating and safety protection functions as claimed in claim 1, wherein a connecting piece made of high-resistance material is connected between the pole and the bimetallic strip, and the connecting piece made of high-resistance material is packaged in the insulating member and insulated from the metal framework of the cover plate.

3. The battery with self-heating and safety protection functions as claimed in claim 1, wherein the battery case made of high-resistance material is made of metal simple substance, alloy, semiconductor, conductive polymer material, and has a resistance of not less than 100m Ω.

4. The battery with self-heating and safety protection functions as claimed in claim 2, wherein the connecting sheet made of high resistance material is made of metal, alloy, semiconductor, conductive polymer material, and has resistance value not less than 100m Ω.

5. The battery with self-heating and safety protection functions as claimed in claim 1, wherein the insulating member is formed by curing a high temperature resistant insulating adhesive.

6. The battery with self-heating and safety protection functions as claimed in claim 1, wherein the battery positive cover plate is provided with a liquid injection hole on the cover plate metal framework, the insulating member forms a groove at two ends of the liquid injection hole, and the liquid injection hole is sealed by a sealing rubber plug.

7. The battery as claimed in claim 1, wherein the battery case is made of a high resistance material and has a positive electrode tab fixedly connected to the positive electrode tab of the positive electrode cap plate and a negative electrode tab fixedly connected to the negative electrode cap plate.

8. The battery with self-heating and safety protection functions as claimed in claim 7, wherein the joints between the pole core and the positive cover plate and the negative cover plate are respectively wrapped with high temperature resistant insulating glue.