CN108832054A - A shell structure of honeycomb automobile battery pack with variable thickness - Google Patents

Abstract

The invention discloses a variable-thickness honeycomb automobile battery pack shell structure. The battery pack shell structure is composed of a shell side wall, a rear end cover and a front end cover. The side wall and rear end cover are honeycomb-filled sandwich structures, and the front end cover is a thin plate structure. The honeycomb wall thickness of the rear end cover increases sequentially along the honeycomb axis from the rear to the front (from the rear to the front), and the thickness of the other thin-walled plates remains unchanged. In the present invention, the side wall of the housing and the rear end cover are designed as a sandwich structure filled with honeycombs, so that the electric bus can greatly absorb the collision energy when a rear-end collision occurs; The front is strong, which can make the structural deformation sequentially, make it stable in energy absorption, reduce the peak acceleration of collision, reduce the intrusion damage to the battery pack, and at the same time, compared with the equal thickness design, it can significantly reduce the quality of the shell.

Description

A shell structure of honeycomb automobile battery pack with variable thickness

technical field

The invention belongs to the technical field of structural design of automobile parts, and in particular relates to a battery pack casing.

Background technique

With the rapid development of electric buses in my country, the lightweight design and safety design of electric bus components have received widespread attention. In the design of electric buses, the safety of the battery and the lightweight of the casing are the focus of engineers' attention. The battery pack housing is located at the rear of the vehicle. When a rear collision occurs, the safety of the battery is greatly challenged, and the battery is extremely vulnerable to damage, fire, or even explosion. Therefore, it is necessary to design an excellent lightweight battery pack shell structure with high strength and rigidity and strong ability to absorb collision energy.

When the electric bus encounters a rear impact, the rear end of the battery pack shell is first crushed and deformed, which greatly absorbs the collision energy and reduces its energy transfer to the battery pack backwards; its front end is strong and not easily deformed, thus ensuring The front of the rear end cover corresponds to the safety space required by the battery pack.

In the design of the battery pack shell in the prior art, it is generally welded by sheet stamping parts of equal strength and thickness. Such a structure cannot fully absorb the collision energy, reduce battery damage, and cannot achieve performance differences at different positions of the structure. Realize lightweight design. Therefore, it is very important to design a battery pack shell structure with good energy absorption effect, flexible performance distribution, and excellent comprehensive performance.

Contents of the invention

The purpose of the invention is to overcome the deficiencies in the existing shell structure and provide a honeycomb battery pack shell structure with variable thickness. The introduction of the honeycomb structure can increase the rigidity of the shell and improve the absorption of collision energy.

The technical scheme provided by the invention is:

A variable thickness honeycomb car battery pack shell structure, including the side wall of the shell, the rear end cover and the front end cover, the side wall is a sandwich honeycomb sandwich structure composed of an outer plate, an inner plate and a honeycomb core, and the rear end cover is composed of an inner The sandwich honeycomb sandwich structure composed of the panel, the outer panel and the honeycomb core, the sandwich honeycomb sandwich structure of the rear end cover is not less than 1/8 of the total shell size, and the width of the sandwich honeycomb sandwich structure of the side wall accounts for 1/ of the total shell width 20-1/10, the thickness of the honeycomb core of the rear end cover increases sequentially along the honeycomb axis from the rear to the front of the vehicle, the thickness of the honeycomb core wall of the body side wall remains unchanged along the honeycomb axis, and the thickness of the honeycomb core wall It is equal to the wall thickness of the front end of the honeycomb core of the rear end cover. The honeycomb core is pressed into a corrugated plate by a corrugated roller, and the sawtooth angle is 120°.

The honeycomb cell section of the honeycomb interlayer is a regular hexagon.

The inner and outer panels of the side wall, the inner and outer panels of the rear end cover and the front end cover are aluminum alloy thin plates of equal thickness.

The base material of the shell structure adopts 3 series aluminum alloy material.

The inner and outer panels of the side wall and the inner and outer panels of the rear end cover are integrated with their respective honeycomb cores by industrial film glue or brazing.

The beneficial effects of the present invention are:

1. The battery pack shell structure of the present invention introduces the honeycomb core sandwich design, which fully utilizes the advantages of the honeycomb structure in terms of specific energy absorption and high specific stiffness, and can significantly increase the impact absorption of the shell compared with the traditional thin-walled plate structure. performance characteristics, while increasing the rigidity of the shell to protect the safety of the battery pack.

2. The honeycomb wall thickness of the rear end cover of the shell increases sequentially from the back to the front of the honeycomb axial direction, that is, the strength is realized to be weak at the rear and strong at the front. Compared with the traditional equal-strength shell structure, it can guarantee The rear end far away from the battery pack is first crushed and deformed, which greatly absorbs the collision energy and reduces the energy transfer to the battery pack; the front end is rigid, which can prevent the deformation from invading the battery pack area and causing damage to the battery.

Description of drawings

Fig. 1 is a schematic diagram of the structural assembly of the battery pack case of the present invention.

Fig. 2a is a schematic cross-sectional view of the side wall of the battery pack case of the present invention.

Fig. 2b is a schematic cross-sectional view of the rear end cover of the battery pack case of the present invention.

Fig. 3 Schematic diagram of the change of the wall thickness of the honeycomb structure.

In the figure, 1-rear end cover, 2-front end cover, 3-side wall outer panel, 4-side wall inner panel, 5-side wall honeycomb core.

Detailed ways

Below in conjunction with accompanying drawing, feature of the present invention and operating strategy are described in further detail by embodiment:

As shown in Figure 1, Figure 2a, and Figure 2b, the structure diagram of the variable-thickness honeycomb battery pack shell includes the side wall of the shell, the rear end cover 1 and the front end cover 2, and the rear end cover and the side wall are sandwiches filled with honeycomb interlayers. The structure is composed of inner plate 3, outer plate 4 and honeycomb core 5. The front end cover is an ordinary thin plate part.

The sandwich honeycomb sandwich structure of the rear end cover is the main energy-absorbing area of the collision. In order to ensure sufficient energy-absorbing characteristics, this part of the structure should not be less than 1/8 of the total shell size. The honeycomb sandwich structure of the side wall bears a small load and is not directly contacted by the impact force, so the width of the side wall accounts for 1/20-1/10 of the total width of the shell, and the side wall can be set as a two-layer honeycomb The specific cross-sectional shape of the sandwich structure is shown in Figure 2a and Figure 2b.

Due to the introduction of the honeycomb sandwich structure, the inner and outer panels of the side wall, the front end cover and the inner and outer panels of the rear end cover are not the main energy-absorbing components, but mainly play the role of connecting the honeycomb cells. The thickness of each panel It can be reduced to 1/10 of the thickness of the traditional shell, that is, 0.15mm-0.2mm.

The selection of the thickness of the honeycomb core wall is the focus of the shell design. Because when the electric bus is subjected to a rear impact, the rear end cover is first subjected to the impact force, and then it is transmitted to the side wall until the shell is crushed. Therefore, in order to ensure that the rear end cover can produce enough deformation to absorb the collision energy, it should also reduce the crushing of the side wall and the front end of the rear end cover to prevent the deformation from invading the battery pack area and causing damage to the battery. Based on this idea, the thickness of the rear end of the rear end cover (t _min ) should be as small as possible, while the thickness of the front end (t _max ) should be as large as possible. According to the characteristics of this deformation, it can be assumed that the distribution of the thickness along the honeycomb axial direction on the rear end cover and the side wall obeys the piecewise function of the incremental exponent function and the constant function (the first special embodiment of the present invention):

In the formula, x is the distance from the back of the rear end cover, m is the gradient index, an important parameter to control the thickness change, _L0 is the total length of the rear end cover, and L is the total length of the shell. The schematic diagram of the change of the specific honeycomb core wall thickness is shown in Fig. 3.

When -1<m<0, the thickness distribution curve of f(x) becomes convex, that is, as x increases, the thickness increases slowly, as shown in curve 3 in Figure 3; when 0<m<1 When m=0, the thickness distribution curve becomes concave, that is, with the increase of x, the thickness increase speed becomes faster, as shown in curve 1 in Figure 3, when m=0, the thickness distribution curve becomes a straight line, as shown in curve 2 in Figure 3 Show. The values of the specific parameters t _min , t _max and m should be determined according to calculation and analysis of the actual structure size.

The honeycomb wall thickness g(x) of the side wall is determined according to t _max , that is to say, the thickness of the honeycomb core wall of the shell side wall remains unchanged along the honeycomb axis, and the thickness of the honeycomb core wall is equal to the honeycomb core of the rear end cover The frontmost wall thickness.

According to the deformation characteristics of the above-mentioned strong rear and weak front, it can be assumed that the distribution of the thickness along the honeycomb axial direction on the rear end cover and the side wall obeys the piecewise function of the constant function (the second special embodiment of the present invention):

In the formula, x _n is equal to L ₀ , but the form of expression is different.

In this implementation case, the thickened honeycomb core structure can be understood as n-segment variable-thickness structures with different thicknesses. The rear end cover has n-segment thickness values that increase from back to front, and the thickness of the n-th segment is the same as the thickness of the side wall honeycomb core. The values are equal.

The inner and outer panels and the honeycomb core mentioned above are all made of 3-series aluminum alloy, mainly considering its good performance after brazing.

For the preparation of the honeycomb core, firstly, the flat roller is pressed into a corrugated board through a corrugated roller, and the sawtooth angle is 120°. Then, according to the required structural strength, it is glued or welded into a honeycomb cell section by using 302 industrial glue or brazing. It is a regular hexagonal honeycomb core. At the same time, the distance between the two wheels of the roller press is controlled by computer programming and other technical means, so that the thickness of the honeycomb core board obeys the step distribution or continuous function distribution. The final prepared honeycomb core and the inner and outer plates are integrated by brazing to form a sandwich structure of honeycomb sandwich.

Claims (5)

1. a kind of Varying-thickness cellular car battery pack shell structure, which is characterized in that side wall, rear end cap and front end including shell Lid, the sandwich honeycomb sandwich construction that side wall is made of outside plate, inner panel and honeycomb core, rear end cap be by inner panel, outer panels and The sandwich honeycomb sandwich construction of honeycomb core composition, the sandwich honeycomb sandwich construction of rear end cap are not less than the 1/ of total shell dimension 8, the width of the sandwich honeycomb sandwich construction of side wall accounts for the 1/20-1/10 of shell beam overall, the thickness of the honeycomb core of rear end cap from The tailstock is axially successively increased to headstock direction along honeycomb, and the honeycomb core wall thickness of side wall is axially remained unchanged along honeycomb, honeycomb The size of core wall thickness is equal to the wall thickness of rear end cap honeycomb core front end, and plate Kun is pressed into corrugated sheet by corrugation Kun by honeycomb core, Sawtooth angle is 120 °.

2. a kind of Varying-thickness cellular car battery pack shell structure according to claim 1, which is characterized in that the bee The honeycomb cell element section of nest interlayer is regular hexagon.

3. a kind of Varying-thickness cellular car battery pack shell structure according to claim 1, which is characterized in that the side wall Inside and outside plate, rear end cap inside and outside panel and drive end bearing bracket be equal thickness aluminium alloy sheet.

4. a kind of Varying-thickness cellular car battery pack shell structure according to claim 1, which is characterized in that the shell The substrate of structure uses the aluminum alloy materials of 3 systems.

5. a kind of Varying-thickness cellular car battery pack shell structure according to claim 1, which is characterized in that the side wall Inside and outside plate and rear end cap inside and outside panel and respective honeycomb core using industrial film glue or soldering connection it is integral.