Steel strip and battery module and electric device

Abstract

The application belongs to the field of power batteries, and particularly relates to a steel belt, a battery module and a power utilization device. The steel belt comprises a steel belt body, the steel belt body has a variable cross-section structure, and the width of the variable cross-section structure is less than the width of the steel belt body. By adopting the special steel belt design and controlling the variable cross-section structure, the steel belt can release pressure in the use of the battery module, so that the battery expansion force in the battery module can be controlled.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of power batteries, and particularly relates to a steel belt, a battery module and an electric device. BACKGROUND

[0002] With the development of the new energy industry, power lithium ion battery systems are pursuing longer service life to meet the corresponding needs of the vehicle end. Under this form, controlling the use environment of the battery monomer in the battery system at the PACK end has become a necessary measure to extend the service life.

[0003] The physical factors affecting the service life of the battery monomer in the system can be roughly divided into temperature and pressure.

[0004] The prior art is to set the initial pre-tightening force of the battery module steel belt on the battery stack and add elastic materials in the middle to alleviate the influence of the expansion force on the service life of the single battery, but only plays a certain role in the initial stage of the battery life, and has no obvious effect in the middle and late stages. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide a steel belt, a battery module and an electric device.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A steel belt, comprising a steel belt body, wherein the steel belt body has a variable cross-section structure; the width of the variable cross-section structure is less than the width of the steel belt body.

[0008] The variable cross-section structure has a variable cross-section coefficient S = d / D; 0.15<=S<=0.4; wherein d is the width of the variable cross-section structure, and D is the width of the steel belt body.

[0009] The variable cross-section structure has a length L, and L<=10mm; preferably, 2mm<=L<=5mm.

[0010] The variable cross-section structure has A, and A<=6.

[0011] The steel belt body is rectangular; preferably, the variable cross-section structure is arranged at the end and the middle position of the two long sides of the steel belt body.

[0012] The steel belt body is provided with a connecting piece corresponding to the variable cross-section structure.

[0013] The application also includes a battery module, comprising a battery pack and the steel belt arranged around the battery pack.

[0014] The battery pack comprises a battery group and end plates arranged on the front and rear sides of the battery group.

[0015] The battery pack comprises a plurality of batteries; and a foam is arranged between adjacent batteries.

[0016] The application also comprises an electrical equipment using the battery module.

[0017] Compared with the prior art, the application has the following beneficial effects:

[0018] The application realizes the pressure release of the steel belt in the use of the battery module by adopting a special steel belt design and controlling the variable cross-section structure, so as to achieve the effect of controlling the battery expansion force in the battery module. Tests show that when the variable cross-section coefficient S of the steel belt is d / D; 0.15≤S≤0.4; and the stress of the steel belt is in the range of 3kN-8kN, the battery can have a longer service life. As a preferred form, the length and position of the variable cross-section structure are designed to meet the more accurate control of the pressure of the battery module. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 An assembly diagram of the battery module of one embodiment of the application;

[0020] Fig. 2 An exploded diagram of the battery module of one embodiment of the application;

[0021] Fig. 3 An assembly diagram of the composite of one embodiment of the application;

[0022] Fig. 4 An exploded diagram of the composite of one embodiment of the application;

[0023] Fig. 5 A main body diagram of the steel belt of one embodiment of the application;

[0024] Fig. 6 A steel belt diagram with multiple variable cross-sections of one embodiment of the application. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0026] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0027] In the description of the present application, it needs to be understood that the terms "installation", "connection", "connection", "setting" should be understood broadly, for example, it can be fixedly connected, set, or detachably connected, set, or integrally connected, set. For those skilled in the art, the specific meaning of the above terms in the present patent can be understood according to the specific circumstances.

[0028] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited.

[0029] Please refer to Figs. 1-6 As shown, the steel strip provided by the present application comprises a steel strip body 1021, and the steel strip body has a variable cross-section structure 10212; Fig. 5 As shown, the width d of the variable cross-section structure is less than the width D of the main part 10211 of the steel strip body. The steel strip is stressed in the range of 3kN-8kN, which can make the battery have a longer service life. According to the number of existing module battery monomers and the number of steel strips, the steel strip variable cross-section coefficient S of the variable cross-section structure is d / D; 0.15≤S≤0.4; wherein d is the width of the variable cross-section structure, and D is the width of the main part of the steel strip body. The length of the variable cross-section structure is L, in order to ensure that the fracture part can produce stress concentration under the specified pressure and fracture, L≤10mm, preferably L≤5mm, preferably 2mm≤L≤5mm.

[0030] In addition, the steel belt can also adopt a plurality of variable cross-section structures to realize more precise control of the battery module pressure. The variable cross-section structure positions are set according to the stress of the steel belt. The stress of the steel belt is most obvious near the two side end plates and the middle part, which can be used as the variable cross-section position. Therefore, the number of variable cross-section structures in the module steel belt is A, A≤6. In use, the steel belt body is a rectangular structure; the variable cross-section structure is arranged at the end and the middle position of the two long sides of the steel belt body.

[0031] The steel belt body is provided with a connecting piece 1022 corresponding to the variable cross-section structure. The steel belt body and the variable cross-section structure are integrally formed, and the connecting piece is connected with the steel belt body in a welding form. The setting of the connecting piece can make the steel belt body not be completely disconnected after the variable cross-section structure is disconnected. First, the steel belt body is slotted at the corresponding variable cross-section structure position, and then the connecting piece is welded at the corresponding position of the variable cross-section structure.

[0032] Figs. 1-2 A battery module 100 is shown, which includes a battery pack 103 and the steel belt 102 arranged around the battery pack. The battery pack includes a battery group and end plates arranged in front and back of the battery group, which are front end plate 101 and rear end plate 102 respectively. The battery group includes a plurality of batteries; the adjacent batteries are provided with foam 104.

[0033] The application also includes a power-using device using the battery module.

[0034] The linear stress mode is selected to simulate the fracture force of the steel belt. The following examples and comparative examples are selected to illustrate the simulation, and the specific parameters are shown in Table 1:

[0035] Table 1

[0036]

[0037]

[0038] Examples 1 and 5 are comparative data within the given standard value range, containing two symmetrically arranged variable cross-section structures, and the variable cross-section coefficients are both 0.15; Example 6 contains four symmetrically arranged variable cross-section coefficient structures, two of which have a symmetric variable cross-section coefficient S1=0.15, and the other two have a symmetric variable cross-section coefficient S2=0.25. Comparative example 1 and comparative example 2 are simulation verification beyond the standard value range.

[0039] The simulation comparison found that the examples set according to the given parameter range can realize the release of the battery swelling force.

[0040] Comparison 1: comparison between example 1 and example 2, only the variable cross-section coefficient S is changed, the breaking force increases from 4.8kN to 6.5kN, which shows that the increase of variable cross-section coefficient can increase the breaking force.

[0041] Comparison 2: comparison between example 1 and example 3, the variable cross-section structure length is shortened. The breaking force decreases from 4.8kN to 4.3kN, which shows that the shortening of variable cross-section structure length can make the stress concentration at the cross-section easier, and achieve the set breaking value.

[0042] Comparison 3: comparison between example 1 and example 6, the number of variable cross-section structures in example 6 is increased. According to the simulation diagram, example 6 can ensure that the battery has good stress for a longer time.

[0043] Comparison 4: comparison between example 1 and comparative example 1, the breaking part length of comparative example 1 is greater than the limit value. The breaking force increases from 4.8kN to 9.2kN, which shows that too large breaking part length cannot make the steel belt break at the design value, affecting the use.

[0044] Comparison 5: comparison between example 1 and comparative example 2, the variable cross-section coefficient of comparative example 2 exceeds the limit value. The breaking force increases from 4.8kN to 12.7kN. It shows that after exceeding the limit value, the design purpose cannot be achieved.

[0045] For the width D of the steel belt, in actual use, it is not limited to the value given in the examples in this paper, when D>15mm, the proportion range corresponding to S will gradually decrease, when D<15mm, the proportion range corresponding to S will gradually increase.

[0046] The above only describes the preferred embodiments of the present application, it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A steel strip for battery modules, characterized in that, The steel band body has a variable cross-section structure; the width of the variable cross-section structure is less than the width of the steel band body; The variable cross-section structure has a variable cross-section coefficient S=d / D; 0.15≤S≤0.4; wherein, d is the width of the variable cross-section structure, and D is the width of the steel band body; The variable cross-section structure has a length L, and L≤10mm; The variable cross-section structure has A, and A≤6; The steel band body is rectangular; The steel band body is provided with a connecting piece at a position corresponding to the variable cross-section structure; and the variable cross-section structure is arranged at the end and the middle of the two long sides of the steel band body.

2. The steel strip for battery module according to claim 1, characterized by 2mm≤L≤5mm.

3. A battery module, characterized by, The application also provides a battery pack and a steel band surrounding the battery pack.

4. The battery module of claim 3, wherein, The battery pack comprises a battery group and end plates arranged on the front and back sides of the battery group.

5. The battery module of claim 4, wherein, The battery group comprises a plurality of batteries, and foam is arranged between adjacent batteries.

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